Methods of welding a bonding connector of a contact plate to a battery cell terminal

ABSTRACT

Embodiments are directed to establishing a direct electrical bond between a bonding connector of a contact plate and a battery cell in a battery module. In a first embodiment, an oscillating laser is used to weld the bonding connector to a battery cell terminal over a target area over which the bonding connector makes non-flush contact. In a second embodiment, the bonding connector is flattened to reduce a gap between the bonding connector and the target area on the battery cell terminal, and then laser-welded (e.g., using an oscillating or non-oscillating laser). In a third embodiment, at least one hold-down mechanism is applied over the bonding connector to secure the bonding connector to the battery cell terminal, after which the bonding connector is laser-welded to the battery cell terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application for patent claims the benefit of U.S.Provisional Application No. 62/408,428, entitled “SANDWICH-CONTACT PLATEFOR ELECTRICAL CONNECTION BATTERY CELLS”, filed Oct. 14, 2016, and alsoof U.S. Provisional Application No. 62/431,067, entitled“SANDWICH-CONTACTPLATE FOR ELECTRICAL CONNECTION BATTERY CELLS”, filedDec. 7, 2016, and also of U.S. Provisional Application No. 62/408,437,entitled “CELL DESIGN FOR CYLINDRICAL CELLS”, filed Oct. 14, 2016, andalso of U.S. Provisional Application No. 62/414,263, entitled “SPECIALFUSE DESIGN FOR ARC AVOIDANCE”, filed Oct. 28, 2016, and also of U.S.Provisional Application No. 62/422,097, entitled “DESIGN OF ELECTRICALCONTACT ON CELL RIM TO OPTIMIZE BUSBAR CROSS-SECTION”, filed Nov. 15,2016, and also of U.S. Provisional Application No. 62/438,800, entitled“DESIGN OF ELECTRICAL CONTACT ON CELL RIM TO OPTIMIZE BUSBARCROSS-SECTION”, filed Dec. 23, 2016, and also of U.S. ProvisionalApplication No. 62/414,224, entitled “CONTACT PLATE FOR OPTIMIZEDCURRENT DENSITY”, filed Oct. 28, 2016, and also of U.S. ProvisionalApplication No. 62/422,099, entitled “INTEGRATED PLUG CONTACT IN CONTACTPLATE OF CELL MODULE”, filed Nov. 15, 2016, and also of U.S. ProvisionalApplication No. 62/422,113, entitled “COOLING SYSTEM FOR BATTERY PACKSWITH HEAT PIPES”, filed Nov. 15, 2016, each of which is by the sameinventors as the subject application, assigned to the assignee hereofand hereby expressly incorporated by reference herein in its entirety.

BACKGROUND 1. Field of the Disclosure

Embodiments relate to methods of welding a bonding connector of acontact plate to a battery cell terminal.

2. Description of the Related Art

Energy storage systems may rely upon batteries for storage of electricalpower. For example, in certain conventional electric vehicle (EV)designs (e.g., fully electric vehicles, hybrid electric vehicles, etc.),a battery housing mounted into an electric vehicle houses a plurality ofbattery cells (e.g., which may be individually mounted into the batteryhousing, or alternatively may be grouped within respective batterymodules that each contain a set of battery cells, with the respectivebattery modules being mounted into the battery housing). The batterymodules in the battery housing are connected to a battery junction box(BJB) via busbars, which distribute electric power to an electric motorthat drives the electric vehicle, as well as various other electricalcomponents of the electric vehicle (e.g., a radio, a control console, avehicle Heating, Ventilation and Air Conditioning (HVAC) system,internal lights, external lights such as head lights and brake lights,etc.).

SUMMARY

An embodiment is directed to a method of establishing a directelectrical bond between a bonding connector of a contact plate and abattery cell in a battery module, including placing the bondingconnector onto a terminal of the battery cell with the bonding connectormaking non-flush contact with the terminal, and oscillating a laser overa target range that encompasses both a point of contact between theterminal and the bonding connector as well as an area where a gap existsbetween the terminal and the bonding connector due to the non-flushcontact, wherein the oscillating results in the bonding connector beingwelded onto the terminal over the target range.

Another embodiment is directed to a method of establishing a directelectrical bond between a bonding connector of a contact plate and abattery cell in a battery module, including flattening the bondingconnector onto a terminal of the battery cell to reduce a gap betweenthe bonding connector and the terminal over a target area, andlaser-welding the flattened bonding connector to the terminal over thetarget area.

Another embodiment is directed to a method of establishing a directelectrical bond between a bonding connector of a contact plate and abattery cell in a battery module, including placing the bondingconnector into contact with a terminal of the battery cell, applying atleast one hold-down mechanism to secure the placed bonding connectoronto the terminal, and laser-welding, during the applying, the placedbonding connector to the terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of embodiments of the disclosure will bereadily obtained as the same becomes better understood by reference tothe following detailed description when considered in connection withthe accompanying drawings, which are presented solely for illustrationand not limitation of the disclosure, and in which:

FIGS. 1-2 illustrate a front-perspective and a back-perspective,respectively, of an exterior framing of a battery module in accordancewith an embodiment of the disclosure.

FIG. 3 illustrates a high-level electrical diagram of an exemplarybattery module that shows P groups 1 . . . N connected in series inaccordance with an embodiment of the disclosure.

FIG. 4 illustrates a side-perspective and a top-perspective of aconventional “Type 1” cylindrical battery cell arrangement.

FIG. 5 illustrates a side-perspective and a top-perspective of aconventional “Type 2” cylindrical battery cell arrangement.

FIG. 6 illustrates a side-perspective and a top-perspective of a “Type1” cylindrical battery cell arrangement in accordance with an embodimentof the disclosure.

FIG. 7A illustrates a hybrid contact plate arrangement in accordancewith an embodiment of the disclosure.

FIG. 7B illustrates the hybrid contact plate arrangement of FIG. 7Abeing arranged on top of P groups 1-5 in accordance with an embodimentof the disclosure.

FIG. 8A illustrates a side-perspective of a “Type 1” cylindrical batterycell arrangement in accordance with another embodiment of thedisclosure.

FIG. 8B illustrates a side-perspective of a “Type 1” cylindrical batterycell arrangement in accordance with another embodiment of thedisclosure.

FIG. 9 illustrates a side-perspective of a portion of a multi-layercontact plate in accordance with an embodiment of the disclosure.

FIG. 10 illustrates a side-perspective of a multi-layer contact plate inaccordance with another embodiment of the disclosure.

FIG. 11 illustrates a top-perspective of a “center” multi-layer contactplate in accordance with an embodiment of the disclosure.

FIG. 12 illustrates a side-perspective of a hybrid contact platearrangement in accordance with an embodiment of the disclosure.

FIG. 13A illustrates a side-perspective of a hybrid contact platearrangement for a battery module in accordance with an embodiment of thedisclosure.

FIG. 13B illustrates a side-perspective of a hybrid contact platearrangement for a battery module in accordance with another embodimentof the disclosure.

FIG. 13C illustrates a side-perspective of a hybrid contact platearrangement for a battery module in accordance with another embodimentof the disclosure.

FIG. 13D illustrates a side-perspective of a hybrid contact platearrangement for a battery module in accordance with another embodimentof the disclosure.

FIG. 13E illustrates the hybrid contact plate arrangement of FIG. 13Dbeing arranged on top of P groups 1-5 in accordance with an embodimentof the disclosure.

FIG. 14 illustrates a deconstructed perspective of various layers of ahybrid contact plate arrangement in accordance with an embodiment of thedisclosure.

FIG. 15A illustrates an example of current density distribution atdifferent areas of the hybrid contact plate arrangement depicted in FIG.14 in accordance with an embodiment of the disclosure.

FIG. 15B illustrates a more detailed view of the hybrid contact platearrangement of FIG. 14 in accordance with an embodiment of thedisclosure.

FIG. 15C illustrates a cooling mechanism for a battery module inaccordance with an embodiment of the disclosure.

FIG. 15D illustrates another perspective of the cooling mechanism ofFIG. 15C in accordance with an embodiment of the disclosure.

FIG. 15E illustrates additional perspectives of the cooling mechanism ofFIG. 15C in accordance with an embodiment of the disclosure.

FIG. 16A illustrates a contact plate that is preassembled with bondingconnectors in accordance with an embodiment of the disclosure.

FIG. 16B illustrates a contact plate with preassembled bonding ribbonsin accordance with another embodiment of the disclosure.

FIG. 16C illustrates a contact plate that is connected to a plurality ofbattery cells in accordance with an embodiment of the disclosure.

FIG. 16D illustrates a top-view of a portion of a multi-layer contactplate in accordance with an embodiment of the disclosure.

FIG. 16E illustrates the portion of the multi-layer contact plate inFIG. 16D with contact tabs being pushed down onto respective negativecell rim(s) of battery cells in accordance with an embodiment of thedisclosure.

FIG. 16F illustrates an example of a bonding connector being welded ontoa positive cell head of a battery cell in accordance with an embodimentof the disclosure.

FIG. 16G illustrates an alternative welding implementation relative toFIG. 16F in accordance with an embodiment of the disclosure.

FIG. 16H depicts a 1-Cell arrangement with one contact area per batterycell in accordance with an embodiment of the disclosure.

FIG. 16I illustrates an arrangement whereby a bonding connector issecured to a terminal of a battery cell at least in part based on amagnetic field that is used as a hold-down mechanism in accordance withan embodiment of the disclosure.

FIG. 16J depicts a hold-down plate mounted on top of a hybrid contactplate arrangement in accordance with an embodiment of the disclosure.

FIG. 16K depicts a different side-perspective of the hold-down platedepicted in FIG. 16J in accordance with an embodiment of the disclosure.

FIG. 16L depicts another different side-perspective of the hold-downplate depicted in FIG. 16J in accordance with an embodiment of thedisclosure.

FIG. 17A illustrates a top-perspective of a portion of a multi-layercontact plate, along with a side-perspective of the multi-layer contactplate that shows the multi-layer contact plate connected to a top-facingpositive terminal of a battery cell in accordance with an embodiment ofthe disclosure.

FIG. 17B illustrates a top-perspective of a portion of the multi-layercontact plate of FIG. 17A including an insulation layer stacked thereonin accordance with an embodiment of the disclosure.

FIG. 17C illustrates a side-perspective of the multi-layer contact plateof FIG. 17C and the insulation layer of FIG. 17B that shows a respectiveconnection to a top-facing positive terminal of a battery cell inaccordance with an embodiment of the disclosure.

FIG. 18A illustrates a conventional multi-terminal cell side of aconventional cylindrical battery cell.

FIG. 18B illustrates a multi-terminal cell side of a cylindrical batterycell in accordance with an embodiment of the disclosure.

FIG. 19 illustrates a side-perspective of the multi-terminal cell sideof FIG. 18B in accordance with an embodiment of the disclosure.

FIG. 20 illustrates a cylindrical battery cell in accordance with anembodiment of the disclosure.

FIG. 21 illustrates a side-perspective and a top-perspective of ahousing including a number of cylindrical battery cells as describedabove with respect to FIG. 20 inserted therein in accordance with anembodiment of the disclosure.

FIGS. 22A-22H each illustrate a different battery module perspective inaccordance with an embodiment of the disclosure. More specifically, eachsuccessive FIG. among FIGS. 22A-22H adds additional components to thebattery module and/or shows a different perspective of the batterymodule.

DETAILED DESCRIPTION

Embodiments of the disclosure are provided in the following descriptionand related drawings. Alternate embodiments may be devised withoutdeparting from the scope of the disclosure. Additionally, well-knownelements of the disclosure will not be described in detail or will beomitted so as not to obscure the relevant details of the disclosure.

Energy storage systems may rely upon batteries for storage of electricalpower. For example, in certain conventional electric vehicle (EV)designs (e.g., fully electric vehicles, hybrid electric vehicles, etc.),a battery housing mounted into an electric vehicle houses a plurality ofbattery cells (e.g., which may be individually mounted into the batteryhousing, or alternatively may be grouped within respective batterymodules that each contain a set of battery cells, with the respectivebattery modules being mounted into the battery housing). The batterymodules in the battery housing are connected to a battery junction box(BJB) via busbars, which distribute electric power to an electric motorthat drives the electric vehicle, as well as various other electricalcomponents of the electric vehicle (e.g., a radio, a control console, avehicle Heating, Ventilation and Air Conditioning (HVAC) system,internal lights, external lights such as head lights and brake lights,etc.).

Embodiments of the disclosure relate to various configurations ofbattery modules that may be deployed as part of an energy storagesystem. In an example, while not illustrated expressly, multiple batterymodules in accordance with any of the embodiments described herein maybe deployed with respect to an energy storage system (e.g., chained inseries to provide higher voltage to the energy storage system, connectedin parallel to provide higher current to the energy storage system, or acombination thereof).

FIGS. 1-2 illustrate a front-perspective and a back-perspective,respectively, of an exterior framing of a battery module 100 inaccordance with an embodiment of the disclosure. In the example of FIGS.1-2, the battery module 100 is configured for insertion into a batterymodule compartment. For example, each side of the battery module 100includes guiding elements 105 to facilitate insertion into (and/orremoval out of) the battery module compartment. In a further example,the guiding elements 105 are configured to fit into grooves inside thebattery module compartment to facilitate insertion and/or removal of thebattery module 100. An insertion-side cover 110 (or endplate) isintegrated into the battery module 100. Upon insertion, theinsertion-side cover 110 may be attached or affixed to the batterymodule compartment (e.g., via fixation points 115, such as bolt-holes,etc.) to seal the battery module 100 inside the battery modulecompartment. While the insertion-side cover 110 is depicted in FIGS. 1-2as integrated into the battery module 100, the insertion-side cover 110may alternatively be independent (or separate) from the battery module100, with the battery module 100 first being inserted into the batterymodule compartment, after which the insertion-side cover 110 isattached.

Referring to FIGS. 1-2, the insertion-side cover 110 includes fixationpoints 115, a set of cooling connections 120, and an overpressure valve125. In an example, the fixation points 115 may be bolt-holes throughwhich bolts may be inserted, and the set of cooling connections 120 mayinclude input and output cooling tube connectors (e.g., through whichcoolant fluid is pumped into the battery module 100 for cooling one ormore cooling plates). The overpressure valve 125 may be configured toopen when pressure inside of the battery module 100 exceeds a threshold(e.g., to avoid an explosion or overpressure by degassing in case of athermal run away of a battery cell in the battery module 100).

Referring to FIG. 2, the battery module 100 further includes a set offixation and positioning elements 200 (e.g., to position and secure thebattery module 100 in the battery module compartment while inserted), aset of HV connectors 205 (e.g., to connect the battery module 100 tocorresponding HV connectors in the battery module compartment), and anLV connector 210 (e.g., to connect internal sensors of the batterymodule 100 to the BJB (not illustrated) via a corresponding LV connectorin the battery module compartment). Accordingly, the battery module 100is configured such that, upon insertion into the battery modulecompartment, the fixation and positioning elements 200, the HVconnectors 205 and the LV connector 210 are each secured and connected(e.g., plugged into) corresponding connectors in the battery modulecompartment.

To provide some context, it will be appreciated that many of the“exterior” components described above with respect to FIGS. 1-2 arespecific to particular battery module compartment configurations (e.g.,configurations where the battery module 100 is configured to be insertedinto a battery module compartment and sealed, with both HV connectors205 being arranged on the same side of the battery module forestablishing an HV electrical connection to an energy storage system).By contrast, many of the embodiments described below relate to“internal” component configurations to facilitate various electricalfunctionality (e.g., although some overlap between the interior andexterior components may occur, such as the HV connectors 205corresponding to a section of a multi-layer contact plate that protrudesoutside the battery module 100, which will be described below in moredetail). In this case, the various exterior components depicted in FIGS.1-2 may not be specifically required to support these electricalfunctions facilitated by the internal battery module configurationsdescribed herein. Accordingly, the battery module 100 and associatedcomponents described with respect to FIGS. 1-2 should be interpreted asone exemplary exterior framing implementation for a battery module,whereas the various internal component configurations may alternativelybe directed to other types of exterior framing (e.g., battery moduleswithout guiding elements 105, battery modules that do not include anintegrated insertion-side cover such as insertion-side cover 110,battery modules that position the HV connectors 205 on different sidesfrom each other, and so on).

As noted above, battery modules, such as the battery module 100 of FIGS.1-2, include a set of battery cells. Each battery cell has a respectivecell-type (e.g., cylindrical, prismatic, pouch, etc.). One example of acylindrical battery cell is an 18650 cell. In 18650 cells, positive andnegative terminal contacts are typically made of nickel-plated steel.

For busbars that connect battery cells to each other within the batterymodule 100, a good electrical conductor, such as aluminum (Al) or copper(Cu), may be used. However, joining steel at the positive and negativeterminal contacts of a battery cell with the busbar is difficult. Acommon technology for this connection is wire bonding, where a thin Albonding wire is connected (e.g., via ultrasonic welding) between thebattery cell and the busbar. Due to the thin diameter of the Al bondingwire, there is a large power loss during operation. Battery cells maythereby be deployed in conjunction with a cooling system to cool thebattery cells. Cooling systems generally consume a high amount ofelectrical power. For example, some conventional cooling systems forcylindrical battery cell configurations that include positive/negativecell terminals at opposite ends attempt to cool the cylindrical batterycells radially, which is inefficient (and thereby very power consuming)because cylindrical battery cells generally conduct more heat axiallyrather than radially. In other words, conventional cooling mechanismsattempt to cool the sides of the cylindrical battery cells (e.g., or byapplying indirect cooling to the cylindrical battery cells over theinsulated busbars or contact plates), instead of attempting to directlyand axially cool the cylindrical battery cells, because directly andaxially cooling the cylindrical battery cells will interfere with cellterminal connections in conventional configurations.

In an embodiment, one of the HV connectors 205 may correspond to anegative (or minus) terminal of the battery module 100, and the other HVconnector 205 may correspond to a positive (or plus) terminal of thebattery module 100. Inside the battery module 100, the set of batterycells may be arranged into a plurality of parallel groups, or “Pgroups”. Each of the P groups may include a plurality of battery cellsconnected in parallel with each other (e.g., to increase current), whilethe P groups are connected in series with each other (e.g., to increasevoltage). The negative terminal of the first series-connected P group iscoupled to the negative terminal (or HV connector 205) of the batterymodule 100, while the positive terminal of the last series-connected Pgroup is connected to the positive terminal (or HV connector 205) of thebattery module 100. An example arrangement of P Groups within thebattery module 300 is described below with respect to FIG. 3.

FIG. 3 illustrates a high-level electrical diagram of a battery module300 that shows P groups 1 . . . N connected in series in accordance withan embodiment of the disclosure. In an example, N may be an integergreater than or equal to 2 (e.g., if N=2, then the intervening P groupsdenoted as P groups 2 . . . N−1 in FIG. 3 may be omitted). Each P groupincludes battery cells 1 . . . M connected in parallel. The negativeterminal of the first series-connected P group (or P group 1) is coupledto a negative terminal 305 of the battery module 300, while the positiveterminal of the last series-connected P group (or P group N) isconnected to a positive terminal 310 of the battery module 300. Thenegative and positive terminals 305 and 310 may each be connected to anHV connector, such as one of the HV connectors 205 described above withrespect to FIGS. 1-2. As used herein, battery modules may becharacterized by the number of P groups connected in series includedtherein. In particular, a battery module with 2 series-connected Pgroups is referred to as a “2S” system, a battery module with 3series-connected P groups is referred to as a “3S” system, and so on.Examples of battery module P group arrangements below are provided withrespect to 2S (e.g., N=2), 3S (e.g., N=3) and 4S (e.g., N=4) systems forthe sake of clarity, although it will be appreciated that embodiments ofthe disclosure may be directed to a battery module with any number ofseries-connected P groups in other embodiments, or even to a batterymodule with a single P group.

FIG. 4 illustrates a side-perspective and a top-perspective of aconventional “Type 1” cylindrical battery cell arrangement 400.Referring to the side-perspective of the “Type 1” cylindrical batterycell arrangement 400 in FIG. 4, a top-facing positive terminal of abattery cell 405 is connected to a contact plate 410 via a bonding wire415, and a top-facing negative terminal of a battery cell 420 isconnected to a contact plate 425 via a bonding wire 430. The batterycells 405 and 420 belong to adjacent P groups and are connected inseries via a bottom-facing positive terminal of the second battery cell420 being connected to a contact plate 435 with a bonding wire 440, anda bottom-facing negative terminal of the battery cell 405 beingconnected to the contact plate 435 via a bonding wire 445. While notshown specifically in FIG. 4, the contact plate 425 may be connected inseries to the positive terminal of another P group or alternatively to anegative terminal for the battery module. Likewise, while not shownspecifically in FIG. 4, the contact plate 410 may be connected in seriesto the negative terminal of another P group or alternatively to apositive terminal for the battery module.

Referring now to the top-perspective of the “Type 1” cylindrical batterycell arrangement 400 in FIG. 4, P groups are configured with a firstterminal orientation whereby battery cells are arranged with top-facingnegative terminals and bottom-facing positive terminals (e.g., such asbattery cell 420) or with a second terminal configuration wherebybattery cells are arranged with top-facing positive terminals andbottom-facing negative terminals (e.g., such as battery cell 405). Afirst P group 460 is shown with the first terminal orientation, while asecond P group 450 is shown with the second terminal orientation. If the“Type 1” cylindrical battery cell arrangement 400 includes no other Pgroups, it will be appreciated that the “Type 1” cylindrical batterycell arrangement 400 represents an example of a 2S system. As will beappreciated, each series-connected P group swaps terminal orientationsrelative to its adjacent P group(s), which makes assembly complex anddifficult.

FIG. 5 illustrates a side-perspective and a top-perspective of aconventional “Type 2” cylindrical battery cell arrangement 500.Referring to the side-perspective of the “Type 2” cylindrical batterycell arrangement 500 in FIG. 5, a top-facing positive terminal of abattery cell 505 is connected to a contact plate 510 via a bonding wire515, and a bottom-facing negative terminal of the battery cell 505 isconnected to a contact plate 520 via a bonding wire 525. The negativecontact plate 520 is located near the bottom of the battery cell 505,and is connected to a contact plate 530 near the top of the battery cell505 via a connector 535. The positive contact plate 530 is connected toa top-facing positive terminal of a battery cell 540 via a bonding wire545. A bottom-facing negative terminal of the battery cell 540 isconnected to a contact plate 550 via a bonding wire 555. Accordingly,the battery cells 505 and 540 belong to adjacent P groups and areconnected in series via the connector 535. While not shown specificallyin FIG. 5, the contact plate 550 may be connected in series to thepositive terminal of another P group or alternatively to a negativeterminal for the battery module. Likewise, while not shown specificallyin FIG. 5, the contact plate 510 may be connected in series to thenegative terminal of another P group or alternatively to a positiveterminal for the battery module.

Referring now to the top-perspective of the “Type 2” cylindrical batterycell arrangement 500 in FIG. 5, in contrast to FIG. 4, each P group isconfigured with the same terminal orientation (e.g., top-facing positiveterminal and bottom-facing negative terminal). A first P group 560(e.g., including battery cell 505) is connected to a second P group 565(e.g., including battery cell 540) via the connector 535. If the “Type2” cylindrical battery cell arrangement 500 includes no other P groups,it will be appreciated that the “Type 2” cylindrical battery cellarrangement 500 represents an example of a 2S system. As will beappreciated, the “Type 2” cylindrical battery cell arrangement 500 doesnot require the terminal orientation switching between adjacent P groupsas in the “Type 1” cylindrical battery cell arrangement 400. However,the “Type 2” cylindrical battery cell arrangement 500 requires aseparate connector (e.g., connector 535) between each adjacent P group.The current flow is routed through these connectors (e.g., connector535), which increases the current density and resistance inside arespective battery module. Moreover, the required space for theconnector 535 decreases maximum cell capacity in the battery module.

Referring to FIGS. 4-5, the “Type 1” cylindrical battery cellarrangement 400 in FIG. 4 and the “Type 2” cylindrical battery cellarrangement 500 in FIG. 5 both require a “turnover” of the battery cellsduring assembly of the battery module. This is required because cellterminal connections are made on both sides (i.e., top and bottom) ofthe battery cells. So, with respect to FIG. 4 as an example, assume thatbattery cells 405 and 420 may be installed into a battery module housingsuch that the “bottom” of the battery cells 405 and 420 (as depicted inFIG. 4) are exposed. At this point, a technician may weld (or otherwisefuse) bonding wires 440 and 445 to the contact plate 435. At this point,the technician cannot reach the cell terminals at the “top” of thebattery cells 405 and 420 (as depicted in FIG. 4), and thereby turnsover (or flips) the battery module housing. Once turned over, thetechnician welds (or otherwise fuses) the bonding wires 415 and 430 tothe contact plates 410 and 425, respectively. As will be appreciated,this “turnover” requirement slows down the bonding process, and can alsobe difficult simply due to the battery modules being relatively heavy.In an example, the “turnover” problem can be avoided in certainembodiments of the disclosure which are described below in more detaildue to both positive/negative cell terminals being arranged on the sameend of the battery cells.

Moreover, referring to FIGS. 4-5, the bonding connectors used in the“Type 1” cylindrical battery cell arrangement 400 in FIG. 4 and the“Type 2” cylindrical battery cell arrangement 500 in FIG. 5 may beconventionally implemented as round wires that are fused via anultrasonic welding process. By contrast, in certain embodiments of thedisclosure, a laser-welding process may be used to form bondingconnectors in a manner that is faster than the conventionalultrasonic-based bonding process described above with respect to FIGS.4-5. For laser welding, materials with the same or similar melting pointmay be used for a reliable connection and/or to increase welding speed.For example, if the positive and/or negative terminals of a particularbattery cell are made from steel (e.g., Hilumin), the bonding connectorbetween the busbar (e.g., a multi-layer contact plate, as describedbelow in more detail) may be made from steel (e.g., Hilumin) or someother material that is compatible with the welding process. However,even though laser welding may be slowed somewhat if the bondingconnectors are made from different materials with differentialelectrical properties, such implementations are still possible and areencompassed by various embodiments of the disclosure (e.g., laserwelding Al to steel, Al to Cu, Cu to steel, etc.). Also, in someembodiments of the disclosure, the bonding connectors are implemented asflat metal bands (or “ribbons”) instead of round wires as in FIGS. 4-5.As noted above, in some embodiments, the bonding connectors may eitherbe mechanically connected to, or integrated within, the contact plate inorder to form the cell terminal connections between battery cellterminals and the contact plate. Laser welding of bonding connectors (orcontact tabs) is discussed in more detail below with respect to FIGS.16A-16L.

Embodiments of the disclosure are thereby directed to multi-layercontact plates which each include at least one primary conductive layerand a cell terminal connection layer. Generally, during operation, mostof the current passing through the multi-layer contact plate is carriedvia the at least one primary conductive layer (e.g., Al or Cu), with thecell terminal connection layer configured to form bonding connectorsthat are configured to connect (e.g., via welding, etc.) to cellterminals of battery cells in one or more P groups. Each cell terminalconnection layer is an integrated part of its respective multi-layercontact plate before the multi-layer contact plates are installed intothe hybrid contact plate arrangement (e.g., in contrast to some type ofwire or welding material that is simply connected to single-layercontact plates to form cell connections during battery module assembly).

In an example, multiple primary conductive layers may be used to“sandwich” the cell terminal connection layer (e.g., the cell terminalconnection layer sits in-between top and bottom primary conductivelayers). Alternatively, a two-layer contact plate may be used, with thecell terminal connection layer being secured to a single conductivelayer without the “sandwich” structure (e.g., the cell terminalconnection layer, such as some type of foil, is cladded (pressed) firmlyagainst the thicker primary conductive layer to form a good contact areaand thereby decrease transition resistance of current flowing betweenthe cell terminal connection layer and the primary conductive layer).

In a further example, the at least one primary conductive layer and thecell terminal connection layer may be made from either the same ordifferent materials. In one example, the at least one primary conductivelayer may be made from Al or Cu, while the cell terminal connectionlayer is made from less-conductive steel to match the steel used for thebattery cell terminals (e.g., as in most cylindrical battery cells, suchas 18650 cells). In another example, if battery cell terminals use Al orCu (e.g., for pouch cells and/or prismatic cells), the at least oneprimary conductive layer may be made from Al or Cu. Even if configuredwith the same (or similar) material, the at least one primary conductivelayer and the cell terminal connection layer may include structuraldifferences, as will be explained below in more detail (e.g., the atleast one primary conductive layer may be made from relatively thickblock(s) of Al or Cu, while the cell terminal connection layer is madefrom a thinner layer of Al or Cu, such as foil, which is secured toand/or sandwiched between the conductive layer(s)).

In an example related to the “sandwich” configuration for themulti-layer contact plate, each multi-layer contact plate may includetop and bottom conductive layers made from a first material (e.g., Al orCu) with a first conductivity, with the cell terminal connection layerbeing sandwiched between the top and bottom conductive layers and madefrom the same or different material (e.g., Al, Cu or steel). In anexample where the cell terminal connection layer is made from a secondmaterial (e.g., steel) with a second conductivity (e.g., lower than thefirst conductivity), the second material may match (or be compatiblewith) the material of the positive and/or negative terminals of thebattery cells. For example, in 18650 cells, the terminals may be acold-rolled, nickel-plated steel sheet. For this material, the bondingconnector in each terminal's contact area may be made from a comparablematerial which facilitates the welding process. However, it is alsopossible to weld disparate materials together, so the cell terminalconnection layer need not match the material of the cell terminals incertain embodiments.

In a further example, the cell terminal connection layer may optionallybe at least partially removed in areas that are not directly alignedwith and/or in close proximity to the contact areas where the cellterminal connection layer is used to form the bonding connectors.Removing the cell terminal connection layer in these areas may help toreduce weight and/or increase the overall conductivity of themulti-layer contact plate. For example, the primary conductive layersmay be more conductive than the cell terminal connection layer, in whichcase extra material for the cell terminal connection layer that is notneeded to form the bonding connectors may increase transition resistancebetween the respective layers and reduce the overall conductivity of themulti-layer contact plate. So, while referred to as a cell terminalconnection “layer”, it will be appreciated that different sections ofthe cell terminal connection layer may actually be separate pieces thatare not in direct contact with each other due to the optional materialremoval.

As will be described below, multi-layer contact plates may be arrangedas part of a “hybrid” contact plate arrangement. The hybrid contactplate arrangement may include a plurality of single-layer and/ormulti-layer contact plates which are each separated from one or moreadjacent contact plates with an insulation layer. In the case of ahybrid contact plate arrangement with multi-layer contact plates, theinsulation layer is made from a different material (e.g., plastic) thaneither the at least one primary conductive layer and/or the cellterminal connection layer, which is one reason why this arrangement ofmulti-layer contact plates is referred to herein as a “hybrid” contactplate arrangement. However, hybrid contact plate arrangements mayalternatively comprise single-layer contact plates, and do not expresslyrequire the multi-layer contact plates described herein. Moreover, thehybrid contact plate arrangement is positioned on one side (e.g., top orbottom) of the respective battery cells. So, while the embodimentsdescribed below depict the hybrid contact plate arrangement beingpositioned on one side of the respective battery cells, this isprimarily for convenience of explanation and the embodiments of thedisclosure are not limited to this configuration.

FIG. 6 illustrates a side-perspective and a top-perspective of a “Type1” cylindrical battery cell arrangement 600 in accordance with anembodiment of the disclosure. In particular, the “Type 1” cylindricalbattery cell arrangement 600 that incorporates multi-layer contactplates, which will be described in more detail below.

Referring to the side-perspective of the “Type 1” cylindrical batterycell arrangement 600 in FIG. 6, each battery cell is implemented as acylindrical “can” that includes both a top-facing positive terminal anda top-facing negative terminal, without any bottom-facing terminals. Incertain embodiments which will be described in more detail below, thetop-facing positive terminal occupies an “inner” top-facing section ofthe battery cell (or cell “head”), while the top-facing negativeterminal occupies an “outer” top-facing section of the battery cellalong the cell periphery (or cell “rim”). As used herein, “top-facing”is relative to how the battery cells are oriented upon insertion into arespective battery housing of a battery module in certain embodiments ofthe disclosure. However, in other embodiments (e.g., where themulti-layer contact plates are arranged on the “bottom” of the batterymodule beneath the battery cells), the positive and negative terminalsmay both be “bottom-facing”. Accordingly, in general, while the positiveand negative terminals are configured on the same “end” of the batterycells, this end need not be the top-facing end of the battery cells inall embodiments.

Referring to FIG. 6, a top-facing positive terminal of a battery cell605 is connected to a first multi-layer contact plate 610 via a bondingconnector 615 (e.g., which may implemented as a thin filament or ribbon,and may be made out of steel, for example), and a top-facing negativeterminal of the battery cell 605 is connected to a second multi-layercontact plate 620 via a bonding connector 625 (e.g., a bonding ribbon).A top-facing positive terminal of a battery cell 630 is connected to thesecond multi-layer contact plate 620 via a bonding connector 635 (e.g.,a bonding ribbon), and a top-facing negative terminal of the batterycell 630 is connected to a third multi-layer contact plate 640 via abonding connector 645 (e.g., a bonding ribbon). In FIG. 6, the batterycells 605 and 630 belong to adjacent P groups and are connected inseries via the second multi-layer contact plate 620.

As will be described below in more detail, the multi-layer contactplates 610, 620 and 640 may each be formed with at least one primaryconductive layer (e.g., Al or Cu) that sandwiches and/or is attached toa cell terminal connection layer (e.g., a thin sheet of Al, Cu or steelsuch as Hilumin), with the bonding connectors 615, 625, 635 and 645being formed from the respective cell terminal connection layers.Alternatively, the contact plates 610, 620 and 640 may be implemented assingle-layer contact plates (e.g., Al or Cu), with the bondingconnectors 615, 625, 635 and 645 being added during assembly of thehybrid contact plate arrangement.

Referring now to the top-perspective of the “Type 1” cylindrical batterycell arrangement 600 in FIG. 6, each P group is configured with the sameterminal orientations, and each battery cell includes both a top-facingpositive terminal and a top-facing negative terminal. A first P group650 (e.g., including battery cell 605 or 630) is connected to a second Pgroup 655 (e.g., including battery cell 605 or 630) in series via thesecond multi-layer contact plate 620. If the “Type 1” cylindricalbattery cell arrangement 600 includes no other P groups, it will beappreciated that the “Type 1” cylindrical battery cell arrangement 600represents an example of a 2S system, with the third multi-layer contactplate 640 configured as a negative terminal (or negative pole contactplate, such as 305 in FIG. 3) for the battery module (e.g., which iseither part of or coupled to one of the HV connectors, such as 205 inFIG. 2), and the first multi-layer contact plate 610 configured as apositive terminal (or positive pole contact plate, such as 310 in FIG.3) for the battery module (e.g., which is either part of or coupled toone of the HV connectors 205). However, as noted above, the number of Pgroups is scalable, such that the third multi-layer contact plate 640may be connected to the positive terminal of another P group to formanother in-series connection. Likewise, while not shown specifically inFIG. 6, the first multi-layer contact plate 610 may be connected inseries to the negative terminal of another P group.

As will be appreciated, because the multi-layer contact plates 610, 620and 640 are each arranged on the same side (e.g., on top) of the Pgroups, the multi-layer contact plates 610, 620 and 640 can be arrangedtogether, along with one or more intervening insulation layers, as ahybrid contact plate arrangement. It will be appreciated that a hybridcontact plate arrangement comprising multiple contact plates on the sameside of the battery cells to facilitate series connections between Pgroups is not possible in the “Type 1” cylindrical battery cellarrangement 400 because the contact plates 410/425 are on a differentside of the battery cells 405 and 420 compared to contact plate 435.Likewise, it will be further appreciated that a hybrid contact platearrangement comprising multiple contact plates on the same side of thebattery cells to facilitate series connections between P groups is notpossible in the “Type 2” cylindrical battery cell arrangement 500because the contact plates 510/530 are on a different side of thebattery cells 405 and 420 compared to the contact plate 520. While manyof the embodiments described below relate to multi-layer contact plates,it will be appreciated that hybrid contact plate arrangements on oneside of the battery cells in a battery module to facilitate in-seriesconnections of P groups can be implemented either with multi-layercontact plates or with single-layer contact plates (e.g., solid contactplates comprising Al or Cu without an integrated cell terminalconnection layer). For single-layer contact plates, the bondingconnectors may be added when welding the single-layer contact plate tocorresponding cell terminals because the cell terminal connection layeris not integrated within the single-layer contact plate (e.g., thebonding connectors may be welded to both the single-layer contact plateand cell terminals during the same welding procedure, because thebonding connectors are not components of the single-layer contactplate).

Moreover, while the multi-layer contact plates 610, 620 and 640 are eacharranged on the same side of the P groups as part of the hybrid contactplate arrangement in FIG. 6, it will be appreciated that the multi-layercontact plates 610, 620 and 640 may also be implemented in legacybattery cell arrangements, such as the “Type 1” cylindrical battery cellarrangement 400 of FIG. 4 or the “Type 2” cylindrical battery cellarrangement 500 of FIG. 5. Accordingly, the multi-layer contact plates610, 620 and 640 are not required to be implemented in the hybridcontact plate arrangement.

As will be appreciated, configuring each battery cell with the sameorientation (e.g., with both a top-facing positive terminal and atop-facing negative terminal) as in FIG. 6 reduces assembly costs andcomplexity. Also, in an example, current conducted over each multi-layercontact plate can use the whole width of the respective multi-layercontact plate (e.g., the at least one primary conductive layer, as wellas the cell terminal connection layer) even though only the cellterminal connection layer is used to form the respective bondingconnectors to the battery cell terminals. Moreover, the problem of highcurrent density over the connector 535 in the “Type 2” cylindricalbattery cell arrangement 500 of FIG. 5 is mitigated in the embodiment ofFIG. 6.

FIG. 7A illustrates a hybrid contact plate arrangement 700A inaccordance with an embodiment of the disclosure. Referring to FIG. 7A, a“negative” HV connector 205 is connected to a “negative pole” contactplate, and a “positive” HV connector 205 is connected to a “positivepole” contact plate (e.g., the respective HV connectors may beintegrated as part of the associated contact plates or simply coupled tothe associated contact plates). Also included as part of the hybridcontact plate arrangement 700A are “center” contact plates 1-4. It willbe appreciated that the hybrid contact plate arrangement 700A isconfigured for a 5S system configuration (e.g., to connect 5 P groups inseries, or N=5). Each contact plate is separated from each other contactplate in the hybrid contact plate arrangement 700A by an insulationlayer 705A, which is one reason why the hybrid contact plate arrangement700A may be characterized as a “hybrid” arrangement.

FIG. 7B illustrates the hybrid contact plate arrangement 700A beingarranged on top of P groups 1-5 in accordance with an embodiment of thedisclosure. The dotted arrows in FIG. 7B convey the flow of currentbetween P groups 1-5 and the respective contact plates. This flow ofcurrent may be facilitated via bonding connectors between individualbattery cell terminals in the respective P groups 1-5 and correspondingcontact plates, which are described in more detail below. Also marked inFIG. 7B are dividers between “adjacent” P groups (e.g., P groups 1-2, Pgroups 2-3, P groups 3-4 and P groups 4-5. In an example, the dividersmay be sections of the hybrid contact plate arrangement 700A occupied bythe insulation layer 705A.

In a further example, the dividers between the respective P groups maybe aligned with dividers between adjacent contact plates on the same“level” of an alternating semi-stacked layout of the contact plateswithin the hybrid contact plate arrangement 700A. For example, the“negative pole” contact plate and “center” contact plates 2, 4 are on alower level of the hybrid contact plate arrangement 700A, and the“center” contact plates 1, 3 and “positive pole” contact plate are on anupper level of the hybrid contact plate arrangement 700A (e.g., in otherembodiments, the level arrangements can be swapped and/or otherwisemodified to accommodate higher or lower numbers of P groups, such thatthe “negative pole” contact plate is on the upper level, etc.). So, onthe lower level, the “negative pole” contact plate is adjacent to“center” contact plate 2, and “center” contact plate 2 is adjacent to“center” contact plate 4. On the upper level, “center” contact plate 1is adjacent to “center” contact plate 3, and “center” contact plate 3 isadjacent to the “positive pole” contact plate. Accordingly, the P group1-2 divider corresponds to a divider between the “negative pole” contactplate and the “center” contact plate 2, and so on.

Moreover, as will be discussed in more detail below, “center” contactplates may include contact areas (or holes) where bonding connectors arefused with battery cell terminals of battery cells in respective Pgroups. These contact areas may be clustered together so that one sideof a “center” contact plate includes all the contact areas forestablishing electrical connections to a first P group, and another sideof the “center” contact plate includes all the contact areas forestablishing electrical connections to a second P group. In certainembodiments, the various P group dividers shown in FIG. 7B may also bealigned with an area of the “center” contact plate between the clusteredP group-specific contact area. So, the battery cells in the P groups maybe clustered in the battery module, and the contact areas that alignwith these battery cells may be likewise clustered in the “center”contact plates of the hybrid contact plate arrangement 700A. It will beappreciated that the contact areas in the “positive pole” contact plateand “negative pole” contact plate are each configured for connection tothe same P group, such that P group-based clustering of contact areas isimplicit.

Below, FIGS. 8A-8B illustrate implementations that are somewhat similarto the hybrid contact plate arrangement 700A depicted in FIGS. 7A-7B,although FIGS. 8A-8B relate to examples involving different number of Pgroups and depict additional detail with respect to the electricalinter-connections between individual batteries of the P groups andcorresponding contact plates.

FIG. 8A illustrates a side-perspective of a “Type 1” cylindrical batterycell arrangement 800A in accordance with another embodiment of thedisclosure. In particular, the “Type 1” cylindrical battery cellarrangement 800A is a more detailed example implementation of the “Type1” cylindrical battery cell arrangement 600 of FIG. 6 for a batterymodule for a 3S system configuration that includes three P groupsdenoted as P groups 1, 2 and 3. So, in context with P groups 1 . . . Nin FIG. 3, N=3 in the example depicted in FIG. 8A. P group 1 includesbattery cells 805A and 810A, P group 2 includes battery cells 815A and820A, and P group 3 includes battery cells 825A and 830A. So, in contextwith battery cells 1 . . . M in FIG. 3, M=2 in the example depicted inFIG. 8A. The various contact plates described below with respect to FIG.8A are described below as multi-layer contact plates (e.g., with anintegrated cell terminal connection layer from which bonding connectorsare formed). However, as noted above, single-layer contact plates (e.g.,without the integrated cell terminal connection layer) may be used inplace of the multi-layer contact plates in other embodiments.

Referring to FIG. 8A, a hybrid contact plate arrangement 835A isdeployed on top of P groups 1-3. The hybrid contact plate arrangement835A is configured with a plurality of contact plates, includingmulti-layer contact plates 845A, 850A, 855A and 860A, and an insulationlayer 865A. The multi-layer contact plate 845A is either part of orcoupled to the negative terminal of the battery module (e.g., 305 ofFIG. 3), and may be referred to as a “negative pole” contact plate.Also, the multi-layer contact plate 860A is either part of or coupled tothe positive terminal of the battery module (e.g., 310 of FIG. 3), andmay be referred to as a “positive pole” contact plate. The multi-layercontact plates 850A and 855A are not directly connected to either thepositive or negative terminals of the battery module, and may thereby bereferred to as “center” contact plates.

Referring to FIG. 8A, a divider 870A, or separation, is configuredbetween the multi-layer contact plates 845A and 855A. Thus, multi-layercontact plates 845A and 855A are insulated from each other and therebynot directly coupled. A divider 875A, or separation, is also configuredbetween the multi-layer contact plates 850A and 860A. Thus, multi-layercontact plates 850A and 860A are insulated from each other and therebynot directly coupled. In an example, the dividers 870A and 875A maycomprise some form of insulation (e.g., part of insulation layer 865A).A number of bonding connectors (e.g., bonding ribbons) 880A are depictedin FIG. 8A, each of which connects a top-facing positive terminal or atop-facing negative terminal of the battery cells 805A through 830A toone of multi-layer contact plates 845A, 850A, 855A and 860A in arespective cell contact area (e.g., an “opening” in the hybrid contactplate arrangement 835A configured over each battery cell), as will bedescribed below in more detail. In an example, the bonding connectors880A may be formed from the cell terminal connection layer of therespective multi-layer contact plates 845A, 850A, 855A and 860A.Alternatively, if some or all of the multi-layer contact plates 845A,850A, 855A and 860A are replaced with single-layer contact plates, thebonding connectors 880A may be added during battery module assembly.

Referring to FIG. 8A, top-facing negative terminals of battery cells805A and 810A in P group 1 are coupled to the multi-layer contact plate845A, while top-facing positive terminals of battery cells 805A and 810Ain P group 1 are coupled to the multi-layer contact plate 850A. Further,top-facing negative terminals of battery cells 815A and 820A in P group2 are coupled to the multi-layer contact plate 850A, while top-facingpositive terminals of battery cells 815A and 820A in P group 2 arecoupled to the multi-layer contact plate 855A. Further, top-facingnegative terminals of battery cells 825A and 830A in P group 3 arecoupled to the multi-layer contact plate 855A, while top-facing positiveterminals of battery cells 825A and 830A in P group 3 are coupled to themulti-layer contact plate 860A. So, P groups 1, 2 and 3 are connected inseries, with the multi-layer contact plate 845A functioning as the“negative pole” contact plate (or negative terminal) of the batterymodule (e.g., as in 305 of FIG. 3), while the multi-layer contact plate860A functions as the “positive pole” contact plate (or positiveterminal) of the battery module (e.g., as in 310 of FIG. 3).

FIG. 8B illustrates a side-perspective of a “Type 1” cylindrical batterycell arrangement 800B in accordance with another embodiment of thedisclosure. In particular, the “Type 1” cylindrical battery cellarrangement 800B is a more detailed example implementation of the “Type1” cylindrical battery cell arrangement 600 of FIG. 6 for a batterymodule with a 2S system configuration that includes two P groups denotedas P groups 1 and 2. So, in context with P groups 1 . . . N in FIG. 3,N=2 in the example depicted in FIG. 8B. P group 1 includes battery cells805B and 810B, and P group 2 includes battery cells 815B and 820B. So,in context with battery cells 1 . . . M in FIG. 3, M=2 in the exampledepicted in FIG. 8B. The various contact plates described below withrespect to FIG. 8B are described below as multi-layer contact plates(e.g., with an integrated cell terminal connection layer from whichbonding connectors are formed). However, as noted above, single-layercontact plates (e.g., without the integrated cell terminal connectionlayer) may be used in place of the multi-layer contact plates in otherembodiments.

Referring to FIG. 8B, a hybrid contact plate arrangement 825B isdeployed on top of P groups 1 and 2. The hybrid contact platearrangement 825B includes multi-layer contact plates 830B, 835B and840B, and an insulation layer 845B. The multi-layer contact plate 830Bis part of and/or coupled to the negative terminal of the batterymodule, and may be referred to as a “negative pole” contact plate. Also,the multi-layer contact plate 840B is part of and/or coupled to thepositive terminal of the battery module, and may be referred to as a“positive pole” contact plate. The multi-layer contact plate 835B is notdirectly connected to either the positive or negative terminals of thebattery module, and may thereby be referred to as a “center” contactplate.

Referring to FIG. 8B, a divider 850B, or separation, is configuredbetween the multi-layer contact plates 830B and 840B. Thus, multi-layercontact plates 830B and 840B are insulated from each other and therebynot directly coupled. The divider 850B may comprise some form ofinsulation (e.g., part of insulation layer 845B). A number of bondingconnectors (e.g., bonding ribbons) 855B are depicted in FIG. 8B, each ofwhich connects a top-facing positive terminal or a top-facing negativeterminal of the battery cells 805B through 820B to one of multi-layercontact plates 830B, 835B and 840B in a respective cell contact area(e.g., an “opening” in the hybrid contact plate arrangement 825Bconfigured over each battery cell), as will be described below in moredetail. In an example, the bonding connectors 855B may be formed fromthe cell terminal connection layer of the respective multi-layer contactplates. Alternatively, if some or all of the multi-layer contact plates830B, 835B and 840B are replaced with single-layer contact plates, thebonding connectors 855B may be added during battery module assembly.

Referring to FIG. 8B, top-facing negative terminals of battery cells805B and 810B in P group 1 are coupled to the multi-layer contact plate830B, while top-facing positive terminals of battery cells 805B and 810Bin P group 1 are coupled to the multi-layer contact plate 835B. Further,top-facing negative terminals of battery cells 815B and 820B in P group2 are coupled to the multi-layer contact plate 835B, while top-facingpositive terminals of battery cells 815B and 820B in P group 2 arecoupled to the multi-layer contact plate 840B. So, P groups 1 and 2 areconnected in series, with the multi-layer contact plate 830B functioningas the “negative pole” contact plate (or negative terminal) of thebattery module (e.g., as in 305 of FIG. 3), while the multi-layercontact plate 840B functions as the “positive pole” contact plate (orpositive terminal) of the battery module (e.g., as in 310 of FIG. 3).

FIG. 9 illustrates a side-perspective of a portion of a multi-layercontact plate 900 in accordance with an embodiment of the disclosure. Inparticular, the multi-layer contact plate 900 is depicted as athree-layer contact plate. In an example, the multi-layer contact plate900 may be based on joining a series of “clad” sheets, which form thelayers of the multi-layer contact plate 900. More specifically, in oneembodiment, the cell connection terminal layer of the multi-layercontact plate 900 is implemented as a middle or intermediate (e.g.,steel) sheet 905 that is joined with more highly conductive (e.g., Al orCu) sheets 910 and 915 (e.g., the primary conductive layers) produced bya cold-welding process. In an example, etching and/or corrosionprocesses, as examples, may be used to remove conductive material fromthe welding partner of the battery cell near contact areas 920. Thecontact area 920 may correspond to the “holes” from which the bondingconnectors are joined to the top-facing terminals of battery cells 805Athrough 830A in FIG. 8A. In other words, the bonding connectors are notthreaded “through” the contact area 920 like a needle (e.g., with thebonding connectors being attached to a top portion of the multi-layercontact plate 900 that is outside of the “hole” or contact area 920).Rather, in certain embodiments, the bonding connectors may be formedfrom an integrated cell terminal connection layer (e.g., theintermediate sheet 905), such that the bonding connectors can be said toprotrude out of (or join with) an interior sidewall of the “hole” orcontact area 920 itself. Hence, bonding connectors configured in thismanner (e.g., from an integrated layer within the multi-layer contactplate) help to form an electrical connection from a cell terminal to aposition “in” the hole, instead of “through” the hole. Accordingly, theportion of the intermediate sheet 905 in the contact area 920 may beused as a bonding connector (or ribbon) to connect to a positive ornegative terminal of a battery cell (e.g., by pushing the bondingconnector downwards and then welding the bonding connector onto a cellterminal). In an example, as will be described below in more detail, theportion of the intermediate sheet 905 in the contact area 920 mayinclude one or more contact tabs that are configured to be welded topositive and/or negative top-facing terminals of a battery cell.

Referring to FIG. 9, the conductive sheets 905-915 may be preparedbefore the joining process that forms the multi-layer contact plate 900in at least one embodiment. For example, the conductive sheets 910 and915 may be stamped (e.g., to create the openings or contact areas, suchas contact area 920 in FIG. 9, where the bonding connectors arepositioned) and then joined with the intermediate sheet 905.Alternatively, instead of stamping, the conductive sheets 910 and 915may undergo drilling, milling, water jet cutting, etching, and/or lasercutting to define the openings or contact areas. In an example,manufacturers may have problems with interrupted geometries, in whichcase the conductive sheets 910 and 915 may be joined via cladding,soldering, brazing or clinching.

Referring to FIG. 9, it will be appreciated that while many of theembodiments described herein are characterized with respect tocylindrical battery cells, a number of these embodiments are alsoapplicable to pouch cells and/or prismatic cells. In an example, batterymodules comprised of battery cells with different cell types may bedeployed in energy systems (e.g., some battery modules may comprisecylindrical battery cells while other battery modules in the same energystorage system comprise pouch cells or prismatic cells).

In cylindrical battery cells, it is common for the cell terminals to bemade from steel, which is one reason why the bonding connectors (e.g.,which may be formed from the intermediate sheet 905 in an example) mayalso be made of steel. However, some pouch cells and/or prismatic cellsuse other materials for their respective cell terminals, such as Al orCu. In an embodiment where the intermediate sheet 905 is selectedspecifically to match the cell terminal material, this means that theintermediate sheet 905 may be made from Al or Cu, resulting in anAl—Al—Al contact plate (e.g., two relatively thick Al primary conductivelayers sandwiching a thinner and more flexible Al-based cell terminalconnection layer, such as Al foil) or an Al—Cu—Al contact plate (e.g.,two relatively thick Al primary conductive layers sandwiching a thinnerand more flexible Cu-based cell terminal connection layer, such as Cufoil).

Moreover, the cell terminal connection layer may itself be subdivided soas to comprise different materials. For example, assume that a “center”multi-layer contact plate is connecting two P groups in series withdifferent materials on their cell terminals (e.g. Cu on negativeterminals and Al on positive terminals), with a first of the P groupscontacting the negative terminals with a first contacting sheet metalsection of the cell terminal connection layer made out of Cu and asecond of the P groups contacting the positive terminals with a secondcontacting sheet metal section of the cell terminal connection layermade out of Al. In an example, the above-noted material differentialbetween the positive and negative terminals may occur with respect to aprismatic cell configuration for a battery module, although it is alsopossible in conjunction with cylindrical cells that are configured withdifferent terminal materials (e.g., positive steel terminal withnegative Al or Cu terminal or vice versa, positive Cu terminal withnegative Al terminal or vice versa, etc.).

So, the Al, Cu or steel sheets are aligned with the contact areas of theP groups. The Al, Cu and steel sheets may then be joined to form a“hybrid” cell terminal connection layer that includes differentmaterials (e.g., Al, Cu or steel) for the bonding connectors withrespect to different contact areas. The “hybrid” cell terminalconnection layer of the “center” multi-layer contact plate may also beused in a “center” two-layer contact plate described below in moredetail.

In a further example, at least one primary conductive layer of themulti-layer contact plate 900 may include different sections made fromdifferent materials. In one particular example, the different sectionsof the at least one primary conductive layer may be aligned with thematerial used for the cell terminal connection layer (or intermediatesheet 905) in those sections. In an example, assume that a “hybrid” cellterminal connection layer in a “center” multi-layer contact plateincludes a first section made from a first material (e.g., Al, Cu,steel, an alloy thereof, etc.) for connecting to cell terminals of afirst P group, and a second section made from a second material (e.g.,Al, Cu, steel, an alloy thereof, etc.) different from the first materialfor connecting to cell terminals of a second P group. The first andsecond sections of the cell terminal connection layer include differentsubsets of bonding connectors for connecting to the first and second Pgroups. In this case, at least one section of the at least one primaryconductive layer aligned with (e.g., positive on top of or below) thefirst and/or second sections of the “hybrid” cell terminal connectionlayer may be made from the same material type (e.g., to reduce atransition resistance as current flows from the bonding connector). So,if one of the bonding connector subsets is made from Al or Cu, theprimary conductive layer section(s) aligned with that bonding connectorsubset may likewise be made from Al or Cu in an example. However, if oneof the bonding connector subsets is made from steel, the primaryconductive layer section(s) aligned with that bonding connector subsetmay be made from a different material (e.g., Al or Cu) because thehigher conductivity of Al or Cu may be more desirable through theprimary conductive layer due to the higher resistance of steelirrespective of the transition resistance.

A primary conductive layer that comprises different material types asnoted in the examples may be referred to as a “hybrid” primaryconductive layer. For multi-layer contact plates with more than oneprimary conductive layer, each primary conductive layer may beconfigured as a hybrid primary conductive layer, although it is alsopossible for a combination of hybrid and non-hybrid primary conductivelayers to be used together in the same multi-layer contact plate. Hybridprimary conductive layers may also be used in conjunction with two-layercontact plates or even single-layer contact plates, and are notnecessarily limited to deployment in multi-layer contact plates havingthree layers as depicted in FIG. 9.

As will be appreciated, two joined plate-layers with differentcoefficients of thermal expansion may bend in response to a change intemperature (e.g., bi-metal effect). To reduce or avoid this bi-metaleffect, in one example, at least three plate-layers (e.g., Al-Steel-Al)may be joined in the multi-layer contact plate 900, as depicted in FIG.9. In other words, the top and bottom conductive sheets 910 and 915being made from the same material (e.g., Al or Cu) may make themulti-layer contact plate 900 fairly resistant to temperature changes.

Alternatively, as noted above, the multi-layer contact plate may beformed from two joined plate-layers having different coefficients ofthermal expansion (e.g., Al-Steel, Cu-Steel, etc.). In this example, thebi-metal effect may have a limited impact on the overall functionalityof the multi-layer contact plate if the cell terminal connection layer(e.g., made from steel) is kept relatively thin.

Alternatively, as noted above, the multi-layer contact plate may beformed from two joined plate-layers of the same material type, andhence, the same coefficients of thermal expansion (e.g., Al—Al, Cu—Cu,etc.). This functions to reduce or avoid the bi-metal problem. Forexample, the two joined plate-layers may include a thick primaryconductive layer (e.g., Al or Cu) joined with a thinner cell terminalconnection layer (e.g., one or more sheets of flexible foil) made fromthe same material.

In one example, the intermediate sheet 905 is stamped beforehand toreduce weight and have material only locally around the contact area 920to ensure the electrical connection between cell and conductive sheets910 and/or 915. Alternatively, instead of stamping, the conductivesheets 910 and/or 915 may undergo drilling, milling, water jet cutting,etching, and/or laser cutting to reduce the material of the intermediatesheet 905. The design of the intermediate sheet 905 in the contact area920 can be made very malleable (e.g., to form the bonding connector thatmay be laser-welded to a terminal of the battery cell). To save space,the thickness and shape of the stamped (e.g., or water drilled, lasercut, etc.) intermediate sheet 905 can be embossed in the conductivesheets 910 and/or 915 (e.g., to compensate for height tolerances amongthe battery cells). By reducing or avoiding the bi-metal effect, thestress between the layers of the multi-layer contact plate 900 at thecontact area 920 of the battery cells will be reduced, and a functionalreliability of the resulting contact will increase.

In an alternative embodiment, the conductive sheets 910 and/or 915 maybe stamped, drilled, milled, water jet cut, etched, and/or laser cut todefine contact areas, and the intermediate sheet 905 may be locallyinserted into these defined contact areas for the welding connection.This insertion can be done, for example, by soldering or brazing,pressing and cold welding, or a process comparable with clinching orriveting.

In a further embodiment, to reduce or avoid contact corrosion betweenthe different materials, a protective layer (or passivation layer suchas metal oxide, etc.) can be applied between conductive sheet 910 andintermediate sheet 905 and/or between the conductive sheet 915 and theintermediate sheet 905. If necessary, the impact of the transitionresistance between the intermediate sheet 905 and the conductive sheets910 and 915 upon current flowing through the multi-layer contact plate900 is mitigated because current flowing through the intermediate sheet905 may move to the conductive sheets 910 and 915.

FIG. 10 illustrates a side-perspective of a multi-layer contact plate1000 in accordance with another embodiment of the disclosure. Referringto FIG. 10, the multi-layer contact plate 1000 includes a relativelythick primary conductive layer 1005, and a relatively thin and flexiblecell terminal connection layer (1040, 1045, 1050). In this embodiment,bonding connectors formed from the cell terminal connection layer (1040,1045, 1050) are radially fixed in holes in the primary conductive layer1005 (e.g., pressed, soldered, welded, etc.).

The primary conductive layer 1005 is depicted in FIG. 10 as includingseparate sections which are each part of the same contact plate, withthe “holes” separating the sections of the primary conductive layer 1005corresponding to contact areas 1025, 1030, 1035 (e.g., such as contactarea 920 of FIG. 9) where connections to top-facing positive and/ornegative terminals of battery cells can be made (e.g., via steel bondingconnectors). In other words, the separate sections of the primaryconductive layer 1005 are all structurally part of the same component,with the “holes” being a result of the cross-section perspective of FIG.10. The portion of the intermediate sheet 905 (or cell terminalconnection layer) that extends into the contact area 920 from FIG. 9 canbe affixed onto respective battery cell terminals (e.g., pressed downand then welded or soldered), as shown at 1040, 1045 and 1050. Morespecifically, 1040, 1045 and 1050 may be bonding connectors (e.g.,bonding ribbons) that are implemented as steel bushings (or contactelements) pressed or soldered onto the respective battery cellterminals. Various ways of affixing bonding connectors of multi-layercontact plates, such as the multi-layer contact plate 1000 of FIG. 10,to respective top-facing terminals of battery cells will be described inmore detail below.

FIG. 11 illustrates a top-perspective of a “center” multi-layer contactplate 1100 in accordance with an embodiment of the disclosure. Inparticular, the “center” multi-layer contact plate 1100 represents anexample of a three-layer contact plate including a top and bottomprimary conductive layers (e.g., Cu, Al, etc.), with a “sandwiched” cellterminal connection layer (e.g., made from Cu, Al, steel, etc.) beingsandwiched between the top and bottom primary conductive layers oversome or all of the “center” multi-layer contact plate 1100. The “center”multi-layer contact plate 1100 includes a plurality of openings, orcontact areas, such as contact areas 1105 and 1120. These contact areasare positioned over battery cells to permit connections betweentop-facing terminals and the “center” multi-layer contact plate 1100 viabonding connectors (e.g., bonding ribbons), which may be formed from the“sandwiched” cell terminal connection layer as described above.

With respect to contact area 1105 of FIG. 11, a bonding connector 1110may be used to form a connection with a top-facing negative terminal ofa battery cell (e.g., in a first P group) that is installed underneaththe contact area 1105. A bonding connector 1115 may be used to form aconnection with a top-facing positive terminal of a battery cell (e.g.,in a second P group) that is installed underneath the contact area 1120.Accordingly, each battery cell in the first P group connects to the“center” multi-layer contact plate 1100 via one of the bondingconnectors 1110, and each battery cell in the second P group connects tothe “center” multi-layer contact plate 1100 via one of the bondingconnectors 1115, to facilitate the in-series connection between therespective P groups.

Referring to FIG. 11, it will be appreciated that the “center”multi-layer contact plate 1100 may correspond to either the “center”multi-layer contact plate 850A or the “center” multi-layer contact plate855A in FIG. 8A, as an example. If the “center” multi-layer contactplate 1100 corresponds to the “center” multi-layer contact plate 850A,then the first P group in FIG. 11 that connects to the “center”multi-layer contact plate 1100 via the bonding connectors 1110corresponds to P group 2 in FIG. 8A, and the second P group in FIG. 11that connects to the “center” multi-layer contact plate 1100 via thebonding connectors 1115 corresponds to P group 1 in FIG. 8A.Alternatively, if the “center” multi-layer contact plate 1100corresponds to the “center” multi-layer contact plate 855A, then thefirst P group in FIG. 11 that connects to the “center” multi-layercontact plate 1100 via the bonding connectors 1110 corresponds to Pgroup 3 in FIG. 8A, and the second P group in FIG. 11 that connects tothe “center” multi-layer contact plate 1100 via the bonding connectors1115 corresponds to P group 2 in FIG. 8A.

While not shown explicitly in FIG. 11, the “negative pole” and “positivepole” multi-layer contact plates 845A and 860A can be configuredsomewhat similarly to the “center” multi-layer contact plate 1100.However, as will be discussed below in more detail, the “negative pole”and “positive pole” multi-layer contact plates 845A and 860A connect asingle P group to either the negative terminal or positive terminal forthe battery module. Accordingly, only one type of bonding connector maybe deployed in the “negative pole” and “positive pole” multi-layercontact plates 845A and 860A, in contrast to the “center” multi-layercontact plate 1100. For example, a “negative pole” multi-layer contactplate may include bonding connectors configured to connect to top-facingnegative terminals of battery cells in a respective P group (e.g.,similar to 1110 of FIG. 11), and “positive pole” multi-layer contactplate may include bonding connectors configured to connect to top-facingpositive terminals of battery cells in a respective P group (e.g.,similar to 1115 of FIG. 11).

With respect to FIG. 11, it will be appreciated that the shapes of thecontact areas 1105 and 1120 defined by the multi-layer contact plate1100 may vary based on a configuration of battery cells within aparticular battery module and/or other design criteria. Generally,contact areas are defined over battery cell terminal connections of abattery module, but otherwise may vary in terms of shape based onvarious design criteria. Accordingly, the shape or layout of contactareas 1105 and 1120 in FIG. 11 merely represents one possible exampleimplementation for a particular battery cell configuration.

With respect to FIG. 11, it will be appreciated that the battery cellsof each P group are clustered together, resulting in the “left” part ofthe multi-layer contact plate 1100 including contact areas for negativeterminal connections to a first P group, and the “right” part of themulti-layer contact plate 1100 including contact areas for positiveterminal connections to a second P group. Generally, the multi-layercontact plate 1100 will collect current from the second P group over thepositive cell connections, and transfer this collected current to thefirst P group over the negative cell connections. Due to this particularclustering of P groups, the current distribution will generally beexpected to be highest in the multi-layer contact plate 1100 in-betweenthe respective P groups (e.g., where all the current from the second Pgroup has been collected but has not yet been transferred to the first Pgroup), as will be discussed in more detail below with respect to FIGS.12-15E.

In conventional battery packs (sometimes referred to as soft packs)deployed in high-power systems (e.g., electric vehicle drive motorsystems), battery cells are connected together within the battery packsto achieve higher voltage and/or current. The battery cells areconnected to each other via conductive single-layer contact plates(e.g., Al or Cu). Conventionally, these contact plates are made fromthin homogeneous flat stamped sheet metal (e.g., homogeneous in terms ofthickness). However, battery cells are typically arranged in batterypacks mostly side-by-side in blocks. Due to this preset arrangement ofthe battery cells, it is difficult to generate a homogeneous currentflow using the above-noted flat homogeneous conducting plates. Forexample, enlarging the width and/or thickness of the flat homogeneousconductive plates would theoretically contribute to a more homogeneouscurrent flow, but enlarging the width and/or thickness in this manner isdifficult in conventional battery packs. Hence, conventional batterypacks may experience very inhomogeneous current distribution with moreresistance in the conductive plate. Additionally, in areas of thebattery pack with low current density, unnecessary conductive material(e.g., Al or Cu) may be included, which adds to the cost of the batterypack.

FIG. 12 illustrates a side-perspective of a hybrid contact platearrangement 1200 in accordance with an embodiment of the disclosure. Inparticular, the hybrid contact plate arrangement 1200 is configured fordeployment in a 2S system that includes two P groups connected inseries. While not drawn to scale, FIG. 12 emphasizes the relativethicknesses of particular contact plates.

As shown in FIG. 12, the hybrid contact plate arrangement 1200 includesa “positive pole” contact plate 1205, a “negative pole” contact plate1210, a “center” contact plate 1215, and an insulation layer 1220. InFIG. 12, the contact plates 1205-1215 each include substantially thesame thickness (e.g., height or depth) throughout the hybrid contactplate arrangement 1200, such that the overall thickness (e.g., height ordepth) of the hybrid contact plate arrangement 1200 is constant. In anexample, the “positive pole” contact plate 1205, “negative pole” contactplate 1210 and “center” contact plate 1215 may be implemented either assingle-layer contact plates (e.g., one primary conductive layer withoutan integrated cell terminal connection layer) or as multi-layer contactplates (e.g., one or more primary conductive layers sandwiching and/orattached to an integrated cell terminal connection layer).

In other embodiments of the disclosure, the thickness of the contactplates may be configured variably (e.g., to achieve a target currentdensity at various locations in a battery module so as to achieve a morehomogeneous current flow). For example, the thickness of the contactplates (e.g., single-layer or multi-layer contact plates) may beconfigured to be larger in sections of the battery module with a highercurrent flow expectation, and lower in sections of the battery modulewith a lower current flow expectation, while maintaining a substantiallyconstant thickness across the entire hybrid contact plate arrangement.Furthermore, via special arrangement of individual inhomogeneous plates(turning), it is possible to further reduce the thickness of the hybridcontact plate arrangement, as will be described below in more detail.

FIG. 13A illustrates a side-perspective of a hybrid contact platearrangement 1300A for a battery module in accordance with an embodimentof the disclosure. In particular, the hybrid contact plate arrangement1300A is configured for deployment in a 2S system (e.g., as describedabove with respect to FIG. 8B) that includes two P groups connected inseries. While not drawn to scale, FIG. 13A emphasizes the relativethicknesses of particular contact plates (e.g., single-layer ormulti-layer contact plates).

As shown in FIG. 13A, the hybrid contact plate arrangement 1300Aincludes a “positive pole” contact plate 1305A, a “negative pole”contact plate 1310A, a “center” contact plate 1315A, and an insulationlayer 1320A. In contrast to FIG. 12, the thicknesses of the contactplates 1305A-1315A may be controlled to increase their respectivethicknesses, or depths, in regions of the battery module with higherexpected current density flow. Accordingly, the “positive pole” contactplate 1305A and “negative pole” contact plate 1310A are configured to bethicker near the respective ends of the hybrid contact plate arrangement1300A (e.g., near the respective poles of the battery module), and the“center” contact plate 1315A is configured to be thickest near itsrespective center or middle section.

FIG. 13B illustrates a side-perspective of a hybrid contact platearrangement 1300B for a battery module in accordance with anotherembodiment of the disclosure. In particular, the hybrid contact platearrangement 1300B is configured for deployment in a 3S system thatincludes three P groups connected in series, such as the “Type 1”cylindrical battery cell arrangement 800A described above with respectto FIG. 8A. While not drawn to scale, FIG. 13B emphasizes the relativethicknesses of particular contact plates.

As shown in FIG. 13B, the hybrid contact plate arrangement 1300Bincludes a “positive pole” contact plate 1305B, a “negative pole”contact plate 1310B, a “center” contact plate 1315B, a “center” contactplate 1320B, and insulation layers 1325B and 1330B. In an example, theinsulation layers 1325B and 1330B may be implemented as one continuouslayer, or alternatively as two separate layers. Similar to the 2S systemexample in FIG. 13A, the thicknesses of the contact plates 1305B-1320Bmay be controlled to increase their respective thicknesses, or depths,in regions of the battery module with higher expected current densityflow. Accordingly, the “positive pole” contact plate 1305B and “negativepole” contact plate 1310B are configured to be thicker near therespective ends of the hybrid contact plate arrangement 1300B (e.g.,near the respective poles of the battery module), and the “center”contact plates 1315B and 1320B are configured to be thicker near theirrespective centers or middle sections.

FIG. 13C illustrates a side-perspective of a hybrid contact platearrangement 1300C for a battery module in accordance with anotherembodiment of the disclosure. In particular, the hybrid contact platearrangement 1300C is configured for deployment in a 4S system thatincludes four P groups connected in series. While not drawn to scale,FIG. 13C emphasizes the relative thicknesses of particular contactplates.

As shown in FIG. 13C, the hybrid contact plate arrangement 1300Cincludes a “positive pole” contact plate 1305C, a “negative pole”contact plate 1310C, “center” contact plates 1315C, 1320C and 1325C, andinsulation layers 1330C and 1335C. In an example, the insulation layers1330C and 1335C may be implemented as one continuous layer, oralternatively as two separate layers. Similar to the 2S system examplein FIG. 13A, and the 3S system example in FIG. 13B, the thicknesses ofthe contact plates 1305C-1325C may be controlled to increase theirrespective thicknesses, or depths, in regions of the battery module withhigher expected current density flow. Accordingly, the “positive pole”contact plate 1305C and “negative pole” contact plate 1310C areconfigured to be thicker near the respective ends of the hybrid contactplate arrangement 1300C (e.g., near the respective poles of the batterymodule), and the “center” contact plates 1315C, 1320C and 1325C areconfigured to be thicker near their respective centers or middlesections.

FIG. 13D illustrates a side-perspective of a hybrid contact platearrangement 1300D for a battery module in accordance with anotherembodiment of the disclosure. In particular, the hybrid contact platearrangement 1300D is configured for deployment in a 5S system thatincludes four P groups connected in series. While not drawn to scale,FIG. 13D emphasizes the relative thicknesses of particular contactplates. Moreover, the hybrid contact plate arrangement 1300D isrepresented in FIG. 13D as a modified version of the hybrid contactplate arrangement 700A described above with respect to FIGS. 7A-7B, withthe contact plates described above in the hybrid contact platearrangement 700A being varied in thickness.

As shown in FIG. 13D, the hybrid contact plate arrangement 1300Dincludes a “positive pole” contact plate, a “negative pole” contactplate, “center” contact plates 1-3, and insulation layer(s) 1305D. In anexample, the insulation layer(s) 1305D may be implemented as onecontinuous layer, or alternatively as two separate layers. Similar tothe 2S system example in FIG. 13A, the 3S system example in FIG. 13B,and the 4S system example in FIG. 13C, the thicknesses of the contactplates may be controlled to increase their respective thicknesses, ordepths, in regions of the battery module with higher expected currentdensity flow. Accordingly, the “positive pole” contact plate and“negative pole” contact plate are configured to be thicker near therespective ends of the hybrid contact plate arrangement 1300D (e.g.,near the respective poles of the battery module), and the “center”contact plates 1-3 are configured to be thicker near their respectivecenters or middle sections.

FIG. 13E illustrates the hybrid contact plate arrangement 1300D of FIG.13D being arranged on top of P groups 1-5 (e.g., similar to FIG. 7B) inaccordance with an embodiment of the disclosure. The dotted arrows inFIG. 13E convey the flow of current between P groups 1-5 and therespective contact plates. This flow of current may be facilitated viabonding connectors between individual battery cell terminals in therespective P groups 1-5 and corresponding contact plates. Also marked inFIG. 13E are dividers between “adjacent” P groups (e.g., P groups 1-2, Pgroups 2-3, P groups 3-4 and P groups 4-5. In an example, the dividersmay be sections of the hybrid contact plate arrangement 1300D occupiedby the insulation layer(s) 1305D.

In a further example, as noted above with respect to FIG. 7B, thedividers between the respective P groups may be aligned with dividersbetween adjacent contact plates on the same “level” of an alternatingsemi-stacked layout of the contact plates within the hybrid contactplate arrangement 1300D. The levels in the hybrid contact platearrangement 1300D as shown in FIGS. 13D-13E are not as clear-cut as inthe hybrid contact plate arrangement 700A of FIGS. 7A-7B where there areseparate upper and lower levels. However, in FIGS. 13D-13E, it will beappreciated that the “flat” side of each contact plate is either alignedwith the upper or lower part of the hybrid contact plate arrangement1300D, which can be used to designate the “level” (e.g., upper or lower)of each contact plate. For example, the “negative pole” contact plateand “center” contact plates 2, 4 are on a lower level of the hybridcontact plate arrangement 1300D, and the “center” contact plates 1, 3and “positive pole” contact plate are on an upper level of the hybridcontact plate arrangement 1300D (e.g., in other embodiments, the levelarrangements can be swapped and/or otherwise modified to accommodatehigher or lower numbers of P groups, such that the “negative pole”contact plate is on the upper level, etc.). So, on the lower level, the“negative pole” contact plate is adjacent to “center” contact plate 2,and “center” contact plate 2 is adjacent to “center” contact plate 4. Onthe upper level, “center” contact plate 1 is adjacent to “center”contact plate 3, and “center” contact plate 3 is adjacent to the“positive pole” contact plate. Accordingly, the P group 1-2 dividercorresponds to a divider between the “negative pole” contact plate andthe “center” contact plate 2, and so on.

Moreover, “center” contact plates may include contact areas (or holes)where bonding connectors are fused with battery cell terminals ofbattery cells in respective P groups. These contact areas may beclustered together so that one side of a “center” contact plate includesall the contact areas for establishing electrical connections to a firstP group, and another side of the “center” contact plate includes all thecontact areas for establishing electrical connections to a second Pgroup. In certain embodiments, the various P group dividers shown inFIG. 13E may also be aligned with an area of the “center” contact platebetween the clustered P group-specific contact area. So, the batterycells in the P groups may be clustered in the battery module, and thecontact areas that align with these battery cells may be likewiseclustered in the “center” contact plates of the hybrid contact platearrangement 1300D. As will be explained below in more detail, thedividing region between the contact areas for the different P groups ina “center” contact plate may be the area of the “center” contact platewith a highest current flow expectation, such that “center” contactplates are made to be thickest in this particular area (e.g., inalignment with the P group divider between the P groups that arespective “center” contact plate is configured to connect in series).This is shown illustratively in FIG. 13E whereby each P group divider isaligned with the thickest section of a corresponding “center” contactplate.

Referring to FIGS. 13A-13E, the contact plates described above may beimplemented as multi-layer contact plates in at least one embodiment.However, this is not strictly necessary in all embodiments, and otherembodiments may relate to single-layer contact plates (e.g., Al or Cu)that do not necessarily stack together as layers in a multi-layercontact plate (e.g., Al-Steel-Al, Cu-Steel-Cu, Al—Al, Cu—Cu, Al-Steel,Cu-Steel, etc.).

FIG. 14 illustrates a deconstructed perspective of various layers of ahybrid contact plate arrangement 1400 in accordance with an embodimentof the disclosure. In particular, the hybrid contact plate arrangement1400 is configured for a 2S system that connects two P groups inparallel, as in FIG. 8B or FIG. 13A for example. It will be appreciatedthat the hybrid contact plate arrangement 1400 is exemplary in natureand does not directly map to each embodiment described above. Forexample, in FIG. 2, the HV connectors 205 are positioned on the sameside of the battery module 100, whereas the positive and negative polesfor the hybrid contact plate arrangement 1400 are located at oppositesides. However, despite these types of implementation differences (e.g.,such as the HV connector locations, etc.), the basic teachings of thevarious embodiments can be used in conjunction together (e.g., contactplates having different thicknesses that align with current distributionexpectations can vary as shown in FIG. 14 in conjunction with any otherembodiment disclosed herein).

Referring to FIG. 14, the hybrid contact plate arrangement 1400 ispositioned on top of a housing 1410 that houses battery cells 1405 withtop-facing positive and negative terminals. In an example, the housing1410 may be made from plastic for low cost and high insulation. Thehousing 1410 is configured to secure the battery cells 1405 and providesupport for the hybrid contact plate arrangement 1400. Moreover, whileonly an upper section of the housing 1410 is depicted in FIG. 14, thehousing 1410 may include additional sections to secure the battery cells1405 (e.g., a lower section underneath the battery cells 1405, and soon).

Referring to FIG. 14, the hybrid contact plate arrangement 1400 ismounted on top of the housing 1410, and includes a “negative pole”contact plate 1415, a “positive pole” contact plate 1420, an insulationlayer 1425, and a “center” contact plate 1430 (e.g., which may beconfigured similarly to the “center” multi-layer contact plate 1100 ofFIG. 11, with a somewhat different contact area shape and arrangement).While not shown expressly, in an example, the contact plates 1415, 1420and 1430 may each be separated from the insulation layer 1425 with arespective optional passivation layer. Moreover, in at least oneembodiment, each of the contact plates 1415, 1420 and 1430 in the hybridcontact plate arrangement 1400 may be implemented as single-layer ormulti-layer contact plates, as described above.

As shown in FIG. 14, the thicknesses, or the depths, of contact plates1415, 1420 and 1430 vary along the length of the hybrid contact platearrangement 1400 similar to the hybrid contact plate arrangement 1300Adescribed above with respect to FIG. 13A. In particular, the “positivepole” contact plate 1420 and “negative pole” contact plate 1415 areconfigured to be thicker near the respective ends of the hybrid contactplate arrangement 1400, and the “center” contact plate 1430 isconfigured to be thicker near its respective center or middle section.So, in at least one embodiment, when stacked together, the thickness ofthe overall hybrid contact plate arrangement 1400 can be substantiallyconstant across the entirety of the battery module even while itsconstituent contact plates vary in thickness at different locations. Ina further embodiment, the thickness of the overall hybrid contact platearrangement 1400 may be further controlled by manipulating the thicknessof the insulation layer 1425 at different locations. In this case, extraconductive material (e.g., Al or Cu, which is generally more expensivethan insulation material such as plastic) beyond the current densityrequirements of the hybrid contact plate arrangement 1400 need not beused to achieve the substantially constant overall thickness of thehybrid contact plate arrangement 1400; instead, extra insulationmaterial (e.g., plastic) may be used.

As will be described below in more detail, in contrast to a staticheight implementation for each contact plate as depicted in FIG. 12,regulating the thickness of the respective contact plates and/orinsulation layer as shown in FIGS. 13A-14 may be used to provide abattery module with a number of benefits. These benefits include (i) areduction of material, costs, and/or weight, (ii) a reduction of innerresistance, (iii) a reduction of design space (height) through thehybrid contact plate arrangement, and/or (iv) an improved relationshipbetween cost of materials and current density.

FIG. 15A illustrates an example of current density distribution atdifferent areas of the hybrid contact plate arrangement 1400 depicted inFIG. 14 in accordance with an embodiment of the disclosure. In FIG. 15A,the hybrid contact plate arrangement 1400 is assumed to be bonded tobattery cells as shown in FIG. 8B. Also, in FIG. 15A, larger arrowsdenote higher amounts of current density at a particular location of the“positive pole” contact plate 1420.

Referring to FIG. 15A, a thinner area 1500A of the “positive pole”contact plate 1420 is near the center of the hybrid contact platearrangement 1400 where the “center” contact plate 1430 (not shown inFIG. 15A) is thicker. A current density of the “positive pole” contactplate 1420 is low in this center-area, as noted at 1505A. This region oflow thickness and low current density maps to where battery cell 815Bconnects to the “positive pole” multi-layer contact plate 840B in FIG.8B. More specifically, the thickness of the “positive pole” contactplate 1420 increases along the direction of the current flow.

As current is added to the “positive pole” contact plate 1420 by thevarious battery cells in a particular P group, the current moves towardsthe positive terminal (or pole) of the battery module. Hence, thecurrent density rises in the direction towards the positive terminal ofthe battery module, and the thickness of the “positive pole” contactplate 1420 increases (e.g., linearly) with the current density, as notedat 1510A, which results in a thicker area 1515A being aligned with ahigher current density area 1520A.

While FIG. 15A is described with respect to the “positive pole” contactplate 1420, it will be appreciated that the approach of aligning thethickness of a contact plate with an expected current densitydistribution can be implemented with respect to any of the contactplates of the hybrid contact plate arrangement 1400, as shown in FIG.15B. As will be appreciated, aligning the thickness(es) of contactplate(s) with an expected current density distribution helps to providea more homogeneous current flow throughout the battery module.

FIG. 15B illustrates a more detailed view of the hybrid contact platearrangement 1400 of FIG. 14 in accordance with an embodiment of thedisclosure. Referring to FIG. 15B, current density distribution andcorresponding contact plate thickness is shown between 1500B-1520B. Forexample, thicker areas with higher current density are shown at 1500B,1510B and 1520B, while thinner areas with lower current density areshown at 1505B and 1515B. Also, at 1525B, a portion of the insulationlayer 1425 is shown in more detail. In particular, the thickness of theinsulation layer 1425 may be customized to provide an overall heightreduction to the hybrid contact plate arrangement 1400 while maintaininga substantially constant height (e.g., such that variations in thethicknesses of the contact plates need not be the only manner in whichthe height of the overall hybrid contact plate arrangement 1400 isregulated).

As noted above with respect to the “center” multi-layer contact plate1100 of FIG. 11, battery cells may be clustered together by P group,resulting in “center” contact plates that include different sectionsallocated to terminal connections with different P groups. Because the“center” contact plate is essentially moving current from one P group toanother P group, the highest current density is generally expected to bein the dividing area between the respective P groups. With respect toFIG. 15B, this means that the thicker areas 1500B and 1520B in the“center” contact plate 1430 may correspond to the portion of the“center” contact plate 1430 that separates the respective P groupterminal connections, with the “center” contact plate 1430 graduallybecoming thinner moving away from this P group terminal connectiondivider region.

As discussed above with respect to FIGS. 15A-15B, current density mayincrease at the positive and negative poles of a battery module (e.g.,near the respective HV connectors 205 described above with respect toFIG. 6B). The HV connectors 205 may have a higher resistance relative tothe resistance of the HV busbars that connect adjacent battery modulesto each other. The higher resistance at these locations may likewisecause an increase in temperature at these locations (e.g., near therespective HV connectors 205 described above with respect to FIG. 6B)which may also spread to the HV busbars. Higher temperatures at theselocations of the battery module limit the maximum power that may becharged or discharged by the battery module. This may be especiallyproblematic for certain high-power applications that require fastcharging (e.g., electric vehicles, which may require charging toapproximately 350 kW in a short period).

Embodiments of the disclosure are thereby related to transferring heataway from the HV connectors of a battery module, which correspond torespective ends of the “positive pole” contact plate and “negative pole”contact plate inside the battery module.

FIG. 15C illustrates a cooling mechanism for a battery module inaccordance with an embodiment of the disclosure. Referring to FIG. 15C,a battery cell 1500C includes a positive or negative terminal that isconnected to a multi-layer contact plate 1505C. The multi-layer contactplate 1505C corresponds to either a “positive pole” contact plate or a“negative pole” contact plate. In an example, the multi-layer contactplate 1505C is directly coupled to one of the HV connectors for thebattery module (e.g., one of the HV connectors 205, which is configuredto connect to a corresponding HV connector that is coupled to an HVbusbar). In another example, the HV connector 205 can be structurallyintegrated with the multi-layer contact plate 1505C itself (e.g., themulti-layer contact plate 1505C extends outside of the battery modulefor connecting to a corresponding HV connector that is coupled to an HVbusbar).

Referring to FIG. 15C, a layer 1510C of thermally conductive andelectrically insulative material is placed in direct contact with aterminal component (e.g., at a positive terminal of the battery moduleor a negative terminal of the battery module). In an example, the layer1510C may comprise an insulation foil (e.g., Kapton foil), ceramicinsulation, anodized aluminum, or a combination thereof (e.g., Kaptonfoil wrapped around anodized aluminum). As used herein, the terminalcomponent refers to any component that conducts heat in response to highcurrent flowing through an associated positive or negative terminal,such as the multi-layer contact plate 1505C and/or its associated HVconnector 205. The layer 1510C is further in direct contact with a heatpipe 1515C. In an example, the heat pipe 1515C may be made from amaterial that is conductive with respect to both temperature andelectricity, in an example. Accordingly, heat from the terminalcomponent (e.g., the multi-layer contact plate 1505C and/or itsassociated HV connector 205) will be transferred away from the terminalcomponent towards the heat pipe 1515C with little to no electricitybeing conducted through the heat pipe 1515C. In an example, the heatpipe 1515C may include a substance that undergoes a phase-change betweenliquid and gas to transfer heat from one end to the other.

FIG. 15D illustrates another perspective of the cooling mechanism ofFIG. 15C in accordance with an embodiment of the disclosure. In FIG.15D, the heat pipe 1515C may be secured via attachment to a housing top1500D (e.g., made from plastic). Moreover, the heat pipe 1515C is shownas extending from the terminal component (e.g., the multi-layer contactplate 1505C and/or its associated HV connector 205) near the top of thebattery module to a lower area of the battery module. In one example, acooling plate may be integrated into the battery module as describedabove, and the heat pipe 1515C may be configured to transfer heat awayfrom the terminal component (e.g., the multi-layer contact plate 1505Cand/or its associated HV connector 205) and towards the cooling plate.

FIG. 15E illustrates additional perspectives of the cooling mechanism ofFIG. 15C in accordance with an embodiment of the disclosure. Inperspectives 1500E and 1520E, the heat pipe 1515C is secured viaattachment to the housing top 1500D in an example. The heat pipe 1515Cis further shown as being positioned underneath the HV connector 205(e.g., the terminal component in this example), with the heat pipe 1515Cbeing bent and coupled to a front plate 1510E. An attachment between theheat pipe 1515C and the front plate 1510E may be configured with goodsurface contact to facilitate heat transfer. The front plate 1510E is inturn coupled to a cooling plate 1515E. While not shown expressly in FIG.15E, the cooling plate 1515E may be cooled via a liquid cooling system.

Referring to FIG. 15E, perspective 1525E, a zoomed-in view of theattachment between the heat pipe 1515C and the terminal component (e.g.,the multi-layer contact plate 1505C and/or its associated HV connector205). In perspective 1525E, the heat pipe 1515C is separated from theterminal component by an electrical insulation layer 1530E and gapfiller 1535E (e.g., thermal interface material, such as caulk). In anexample, the electrical insulation layer 1530E may correspond to thelayer 1510C described above with respect to FIG. 15C, which may beformed from a thermally conductive and electrically insulative material.In another example, the electrical insulation layer 1530E and gap filler1535E together may comprise the layer 1510C.

Hence, with respect to FIGS. 15C-15E, heat from the terminal component(e.g., the multi-layer contact plate 1505C and/or its associated HVconnector 205) is transferred to the heat pipe 1515C (e.g., via thelayer 1510C), which then transfers the heat to the cooling plate 1515E(e.g., via the front plate 1510E), which is then cooled via a liquidcooling system (not shown in FIGS. 15C-15E). Moreover, the heat pipe1515C is described as being connected to a generic terminal component ofthe battery module, which corresponds to either the positive terminal orthe negative terminal of the battery module. In an example, two separateheat pipes 1515C may be deployed in the battery module, with a firstheat pipe 1515C being deployed with respect to a first terminalcomponent at the positive terminal, and a second heat pipe 1515C beingdeployed with respect to a second terminal component at the negativeterminal. Both heat pipes 1515C may be configured substantially as shownabove with respect to FIGS. 15C-15D, except for being deployed withrespect to terminal components at different terminals (or poles) of thebattery module. Also, while FIGS. 15C-15E include reference to themulti-layer contact plate 1505C, it will be appreciated that heat beingconcentrated near the HV connectors 205 will likewise occur if asingle-layer contact plate is used. Hence, another embodiment isdirected to a heat pipe arrangement as shown in FIGS. 15C-15E withrespect to a single-layer contact plate.

In some of the embodiments noted above, reference is made to bondingconnectors that are used to connect battery cell terminals to acorresponding contact plate. In an embodiment, these bonding connectorsmay be implemented as ultrasonically welded wire bonds. However,ultrasonic welding requires a lot of time due to the high number ofconnections. This increases throughput time for the production line.Also, the cross-section is limited in ultrasonic welding (e.g., suitablefor round wire welding, but less suitable for welding larger surfaceareas such as flat metal bonding ribbons).

In some embodiments of the disclosure, bonding connectors may be formedfrom a cell terminal connection layer (e.g., part of a multi-layercontact plate as described above). In this case, the bonding connectorsare integrated (or preassembled) into the structure of the multi-layercontact plate, in the sense that no additional welding is required tosecure the bonding connectors to the multi-layer contact plate duringassembly of the battery module. In another embodiment of the disclosure,contact plates (e.g., single-layer or multi-layer) may be preassembledwith bonding connectors that are implemented as laser-welded bondingribbons (e.g., which are not necessarily formed from an integrated layerof the contact plate, but rather may be bonded onto the contact platespecifically near the contact areas), as discussed below with respect toFIG. 16A. Hence, the assembly of the battery module can be simplifieddue to the bonding ribbons already being integrated into theirrespective contact plates (e.g., irrespective of whether a multi-layercontact plate is used). For example, the contact plates may be producedon a separate production line from the production line that produces thebattery modules.

FIG. 16A illustrates a contact plate 1600A that is preassembled withbonding connectors in accordance with an embodiment of the disclosure.In an example, the contact plate 1600A may be preassembled with bondingconnectors 1605A using a laser-welding process. In an example, thebonding connectors 1605A may be formed from the same material (or acompatible material) with respect to the battery terminals to which thebonding connectors (e.g., steel, such as Hilumin), although differentmaterials may also be used (e.g., a steel battery cell terminal may bebonded to an Al or Cu bonding connector, etc.). In a further example,each preassembled bonding connector 1605A may be installed (or welded)into a corresponding groove 1610A in the contact plate 1600A. In anexample, using the groove 1610A helps to reduce the overall height (orthickness/depth) of the contact plate 1600A because the preassembledbonding connectors (e.g., laser-welded bonding ribbons) will not add tothe overall height (or thickness/depth) of the contact plate 1600A.

FIG. 16B illustrates a contact plate 1600B with preassembled bondingribbons in accordance with another embodiment of the disclosure. In anexample, the contact plate 1600B may be preassembled with bondingconnectors 1605B using a laser-welding process. However, in contrast toFIG. 16A, the bonding connectors 1605B are installed directly on a topsurface of the contact plate 1600B (not in a groove). Accordingly, thebonding connectors 1605B contribute to the overall height (orthickness/depth) of the contact plate 1600B. In this case, an insulationlayer 1610B may include grooves 1615B configured to fit thecorresponding bonding connectors 1605B. So, when the various layers ofthe hybrid contact plate arrangement are stacked during assembly of thebattery module, the bonding connectors 1605B will not contribute to theoverall height (or thickness/depth) of the hybrid contact platearrangement and/or the battery module, as shown in FIG. 16B.

As will be appreciated, using contact plates with preassembled bondingconnectors as shown in FIGS. 16A-16B may provide a variety of benefitsto battery modules. These benefits include (i) facilitating the use of aparallel production line, leading to reduced production time for batterymodules, (ii) facilitating the use of preassembly by a separate entitysuch as a supplier (e.g., although in alternative embodiments, a batterymodule assembler could also be the producer of the contact plates withpreassembled bonding ribbons), and (iii) variability in length andposition (very flexible). It will be appreciated that these samebenefits may also be achieved using bonding connectors in multi-layercontact plates formed from an integrated cell terminal connection layer,as described above. Accordingly, attaching bonding connectors to thecontact areas of a contact plate (e.g., as in FIGS. 16A-16B) and formingbonding connectors from an integrated cell terminal connection layer ofa multi-layer contact plate (e.g., as in FIG. 9, FIG. 11, etc.)constitute two alternative ways of preassembling a contact plate withbonding connectors (e.g., preassembled in the sense that the bondingconnectors are part of the associated contact plate before batterymodule assembly, such that a technician need not weld the bondingconnectors to the contact plate during battery module assembly).

FIG. 16C illustrates a contact plate 1600C that is connected to aplurality of battery cells in accordance with an embodiment of thedisclosure. Referring to FIG. 16C, battery cells are grouped together inshared contact areas that include either a 2-Cell or 3-Cell arrangement.For example, contact area 1605C depicts a 3-Cell arrangement and contactarea 1610C depicts a 2-Cell arrangement. In an example, each positivecell head of each battery cell may be connected to a contact plate via arespective bonding connector, such as bonding connector 1615C, which maybe preassembled as discussed above with respect to FIGS. 16A-16B and/orformed from an integrated cell terminal connection layer of amulti-layer contact plate as discussed above with respect to FIGS. 9 and11. In a further example, each negative cell rim (or negative terminal)of each battery cell may be connected to a contact plate via a bondingconnector that is implemented as a contact tab integrated into thecontact plate. During assembly, the contact tab may be affixed to one ormore respective negative cell rims (e.g., by being pressed downward andwelded onto a region that includes portions from each of the one or morenegative cell rims). For example, contact tab 1620C is shown in contactwith negative cell rims of two adjacent battery cells.

In an example, the contact plate 1600C may be configured as either asingle-layer contact plate or a multi-layer contact plate as notedabove. In an example where the contact plate 1600C is implemented as amulti-layer contact plate, the contact areas 1605C and 1610C and contacttabs 1620C may correspond to locations where the primary conductivelayer(s) of the contact plate 1600C are “stamped” (e.g., or, instead ofstamping, the contact areas or holes in the primary conductive layer(s)may be defined by drilling, milling, water jet cutting, etching, and/orlaser cutting). So, when joined with the cell terminal connection layer(e.g., made from flexible steel, such as foil), the stamped (e.g., orwater drilled, laser cut, etc.) areas of the primary conductive layer(s)form the contact tabs 1620C (e.g., the contact tabs 1620C are portionsof the multi-layer contact plate where the flexible cell terminalconnection layer may be moved downwards towards the negative cellterminals).

Referring to FIG. 16C, “high-fuse” bonding connectors 1625C and 1630Care depicted. The “high-fuse” bonding connectors 1625C and 1630C arespecial higher-resistance bonding connectors configured to break lastamong bonding connectors for a particular P group. Accordingly, the“high-fuse” bonding connectors 1625C and 1630C are connected todifferent P groups. More specifically, a lower-resistance section of the“high-fuse” bonding connectors 1625C and 1630C are marked in FIG. 16C,which has a lower resistance than the remainder of the “high-fuse”bonding connectors 1625C and 1630C while still having a higherresistance than any other bonding connector associated with a respectiveP group. “High-fuse” bonding connectors are described in more detailbelow with respect to FIGS. 17A-17C.

FIG. 16D illustrates a top-view of a portion of a multi-layer contactplate 1600D in accordance with an embodiment of the disclosure. Themulti-layer contact plate 1600D is corrugated so as to include aplurality of contact tabs 1605D (e.g., formed from a cell terminalconnection layer of the multi-layer contact plate 1600D) that arearranged around respective contact areas, such as contact areas 1610D. Apositive terminal bonding connector 1615D, which may correspond to oneof the preassembled bonding connectors described above with respect toFIGS. 16A-16B and/or formed from an integrated cell terminal connectionlayer of the multi-layer contact plate as discussed above with respectto FIGS. 9 and 11 in an example, is also shown with respect to one ofthe contact areas 1610D. In an example, the positive terminal bondingconnector 1615D may be connected to a different contact plate that isstacked with the multi-layer contact plate 1600D in a hybrid contactplate arrangement, as described above with respect to FIG. 14, forexample. The contact tabs 1605D may be used to facilitate a connectionto respective top-facing negative terminals (or negative cell rims) ofbattery cells via laser welding or projection welding, as will bedescribed below in more detail.

While FIG. 16C illustrates contact areas 1605C and 1610C encompassingmultiple battery cells (e.g., 2-Cell arrangement or 3-Cell arrangement),in other embodiments, each contact area may be deployed with respect toa single cell (or 1-Cell arrangement). An example of a 1-Cellarrangement is depicted in FIG. 16D, as well as FIGS. 16E-16F which aredescribed below in more detail. These alternative descriptions emphasizethe various embodiment alternatives that are encompassed by the presentdisclosure. It will be appreciated that the various embodimentsdescribed below (e.g., the laser welding techniques described withrespect to FIG. 16F-16G, etc.) are applicable not only to 1-Cellarrangements, but rather any N-Cell arrangement (e.g., 1-Cell, 2-Cell,3-Cell, etc.).

Referring to FIG. 16D, the contact tabs 1605D are each arranged around arespective contact area 1610D in a “circular” manner. In an example,each respective contact area 1610D may be configured to be directlyabove at least one positive cell head of at least one battery cell towhich a bonding connector for that contact area is to be joined. Asshown in FIG. 16C, the contact area need not be circular as illustratedin FIG. 16D. In the example shown in FIG. 16D, there are three contacttabs 1605D that encircle the contact area 1610D (e.g., each offset by120 degrees radially). While not shown expressly in FIG. 16D, threecontact tabs 1605D may encircle each contact area of the multi-layercontact plate 1600D. The radial distance of the contact tabs 1605D fromthe center-point of a respective contact area 1610D may be scalable toachieve one or more design objectives. For example, a smaller radialdistance can be used to achieve an increased cross-section at thebusbar, as well as to reduce a resistance associated with a battery cellconnection and thereby increase current capacity. In a further example,each contact tab 1605D may be spring-loaded to facilitate laser weldingby achieving a near-zero gap to a respective battery cell (e.g., thepositive cell head or negative cell rim of the battery cell) andcompensate tolerances. Alternatively, each contact tab 1605D may beconfigured to be pressed downwards onto a respective battery cell tofacilitate projection welding or resistance welding.

Referring now to FIG. 16E, the contact tabs 1605D are shown in a stateof being pushed down onto respective negative cell rim(s) of batterycells. As the contact tabs 1605D are pushed downwards, the contact tabs1605D become bonding connectors (or bonding ribbons), which may beconfigured somewhat similarly to the positive terminal bondingconnectors 1615D described above. However, in at least one embodiment,each positive terminal bonding connector 1615D is connected to a singlepositive cell head, while each negative terminal bonding connectorformed from a respective contact tab 1605D may be connected to multiplenegative cell rims as depicted in FIG. 16C. Accordingly, in FIG. 16E,contact tabs 1605D are shown in the act of being pushed down ontorespective negative cell rims. In at least one embodiment, the bondingconnector 1615D and contact tabs 1605D depicted in FIGS. 16D-16E mayeach be made from steel (e.g., Hilumin), although the contact tabs 1605Dmay alternatively be made from other materials (e.g., Al, Cu, etc.).

Moreover, while FIGS. 16D-16E illustrate an implementation where“negative” bonding connectors are constructed from contact tabs 1605Dformed from the cell terminal connection layer of the multi-layercontact plate 1600D, other embodiments may be directed to positivebonding connectors formed from contact tabs as well.

In a further example, while the contact tabs 1605D may be constructedfrom the cell terminal connection layer of a multi-layer contact platealigned with stamped (e.g., or water drilled, laser cut, etc.) sectionsfrom the top and bottom conductive layers as noted above, in otherembodiments a single-layer contact plate may be used. In this case, thesingle-layer contact plate (e.g., solid or non-layered Al or Cu) may bestamped, drilled, milled, water jet cut, etched, and/or laser cut toproduce holes, with a contact tab compound (e.g., steel, Al, Cu, etc.)being locally inserted into these holes to produce the contact tabs(e.g., similar to how the bonding connectors are added to the contactplates as shown in FIGS. 16A-16B).

For laser welding, it is generally necessary to have a very small gap orideally no gap between the two components being welded together.Therefore, contact tabs may be fabricated to be spring-loaded on thenegative cell rim or on the positive cell head, depending on whether thecontact tab is configured to be deployed on the positive or negativeterminal of the battery cell. Due to manufacturing tolerances, however,there may be small differences in the exact welding position.

FIG. 16F illustrates an example of a bonding connector 1600F beingwelded onto a positive cell head 1610F of a battery cell 1605F inaccordance with an embodiment of the disclosure. The battery cell 1605Falso includes a negative cell rim 1615F-1620F. In an example, thebonding connector 1600F may be a preassembled bonding connector that iswelded onto a contact plate as described above with respect to FIGS.16A-16B, or alternatively may be formed from an integrated cell terminalconnection layer of a multi-layer contact plate as described above withrespect to FIGS. 9 and 11.

As shown in FIG. 16F, a contact point 1625F where the bonding connector1600F meets the positive cell head 1610F may be at an angle, such thatthe bonding connector 1600F does not sit “flush” on top of the positivecell head 1610F and instead only makes direct contact at the contactpoint 1625F. More specifically, the contact point 1625F may refer to anarea where an edge of the bonding connector 1600F directly contacts thepositive cell head (e.g., assuming the bonding connector 1600F is notbent). In an example, the laser welding between the bonding connector1600F and the positive cell head 1610F may be implemented via anoscillator (e.g., an oscillating laser). By oscillating the laser over aparticular range 1630F, the area in which the bonding connector 1600F iswelded to the positive cell head 1610F may be increased. Hence, via theuse of an oscillating laser, good welding between the bonding connector1600F and the positive cell head 1610F may be achieved over an area thatextends beyond the area where direct (or close) contact between thebonding connector 1600F and the positive cell head 1610F is presentprior to the welding.

FIG. 16G illustrates an alternative welding implementation relative toFIG. 16F in accordance with an embodiment of the disclosure. Referringto FIG. 16G, a bonding connector 1600G is flattened on top of a positivecell head 1610G of a battery cell 1605G prior to welding. The batterycell 1605G also includes a negative cell rim 1615G-1620G.

As shown in FIG. 16G, instead of a narrow point of direct contactbetween the bonding connector and positive cell head prior to welding asin FIG. 16F, by virtue of being “flattened”, the bonding connector 1600Gis flush with the positive cell head 1610G over a target range or targetarea 1625G. In an example, the bonding connector 1600G may be flattenedby applying a hold-down component over the bonding connector 1600G andexerting downward force. In a further example, the hold-down componentmay correspond to a sapphire glass component. By flattening the bondingconnector 1600G over the target range 1625G, a zero or near-zero gapbetween the bonding connector 1600G and the positive cell rim may beachieved over the target range 1625G prior to welding as shown at 1630G,which improves the transition (e.g., increasing current flow andreducing resistance) between the bonding connector 1600G and thepositive cell head 1610G. In an example, an oscillating laser need notbe used for welding in FIG. 16G due to the flattening that occurs priorto welding, although this is still possible.

In a further embodiment with respect to the bonding connector weldingexamples described with respect to FIGS. 16F-16G, soldering (or welding)of a bonding connector to a positive or negative terminal of a batterycell may be facilitated via a soldering compound. In one example, thesoldering compound may include a reactive multi-layer foil (e.g.,NanoFoil or similar product). The soldering compound may be glued orprinted onto a respective bonding connector and, once soldered, may helpto form the electrical connection (or electrical bond) between therespective contact plate and a respective terminal of the battery cell.In an example, the soldering compound is separate from the bondingconnector itself.

In an example where the soldering compound includes a reactivemulti-layer foil, the reactive multi-layer foil may be activated by asmall pulse of localized energy from electrical, optical, and/or thermalsources. When activated, the reactive multi-layer foil may be configuredto react exothermically to precisely deliver localized heat (e.g., up totemperatures of 1500° C.) in a fraction (e.g., on the order ofthousandths) of a second.

It will be appreciated that a conventional laser typically includes asingle beam, which may be used to weld at one particular point or alongone particular line. In a further embodiment with respect to the bondingconnector welding examples described with respect to FIGS. 16F-16G, adiode laser may be used to weld a defined pattern over a broader area.With diode lasers, it is possible to speed up the welding processbecause the entire target welding area can be heated up concurrently.The heat impact to the battery cell is also reduced due to the reducedwelding time in comparison with a standard laser welding process.

FIG. 16H depicts a 1-Cell arrangement 1600H with one contact area perbattery cell in accordance with an embodiment of the disclosure. In anexample, the 1-Cell arrangement 1600H of FIG. 16H may be based on thecontact plate described above with respect to FIGS. 16C-16D, withbonding connectors being welded onto positive and negative terminals ofrespective battery cells as described above with respect to FIGS.16F-16G. For example, “negative” bonding connectors 1605H and 1610H arewelded to negative terminals (or a negative cell rim) of a battery cell,while a “positive” bonding connector 1615H is welded to a positiveterminal 1620H (or positive cell head) of the battery cell.

As noted above, for fixation purposes (e.g., laser welding), closecontact between the parts is generally desired (e.g., although anoscillator laser can be used to accommodate larger gaps as describedabove), with little to no gap between the bonding connector and theterminal of the battery cell. In further embodiments, one or more“hold-down” mechanisms can be used to tightly secure the bondingconnector to the terminal of the battery cell prior to welding. Thesehold-down mechanisms may be permanent components of a respective batterymodule, or alternatively may be non-permanent (e.g., used until thebonding connector is affixed, or welded, to a respective battery cellterminal, and then removed).

In a first embodiment, which is illustrated in FIG. 16I, magnetic-basedfixation may be used as a hold-down mechanism to secure bondingconnectors to a respective terminal of a battery cell prior to welding.More specifically, to facilitate contact between the battery cellterminal and the bonding connector, a magnetic field may be induced inproximity to the battery cell terminal, such that the bonding connectoris magnetically attracted to the battery cell terminal. The permanentposition of the bonding connector can then be fixed through a fixationprocess such as laser welding.

FIG. 16I illustrates an arrangement whereby a bonding connector 1600I issecured to a terminal of a battery cell 1605I at least in part based ona magnetic field that is used as a hold-down mechanism in accordancewith an embodiment of the disclosure. The embodiment of FIG. 16I may bedeployed in conjunction with any of the bonding connector fixation (orwelding) techniques described herein. The battery cell 1605I includes apositive cell head 1610I, and a negative cell rim 1615I and 1620I. InFIG. 16I, the bonding connector 1600I is placed into contact with thepositive cell head 1610I. To help secure the bonding connector 1600I tothe positive cell head 1610I prior to welding, a magnetic field isapplied to secure the bonding connector 1600I onto the positive cellhead 1610I. In one example, a magnet 1625I is arranged beneath thebattery cell 1605I. In an example, the magnet 1625I may be placed underor around the battery cell 1605I prior to the welding of the bondingconnector 1600I to the positive cell head 1610I. More specifically,while not shown expressly in FIG. 16I, the battery cell 1605I may beplaced into a relatively thin battery housing (e.g., made from plastic),along with a number of other battery cells. The magnet 1625I may beplaced beneath the battery housing to induce the magnetic fielddescribed above (e.g., with respect to the battery cell 1605I and/orother battery cells in the battery housing). Accordingly, the magnet1625I need not be in direct contact with the battery cell 1605I. In afurther example, the magnetic field induced by the magnet 1625I may beelongated by metallic properties of the battery cell 1605I, such thatthe bonding connector 1600I becomes magnetically attracted to thepositive cell head 1610I. In an example, after the fixation of thebonding connector 1600I to the positive cell head 1610I, the magnet1625I may optionally be removed from the battery housing.

While FIG. 16I illustrates an example where a separate magnet isdeployed to facilitate magnetic attraction between the bonding connector1600I and the positive cell head 1610I to function as a hold-downmechanism, in another embodiment of the disclosure, the battery cell1605I itself may be magnetized to facilitate the magnetic attraction.For example, each battery cell may be passed through a magnetic coilprior to insertion into the battery housing. In this case, the magnet1625I may be omitted. Alternatively, the magnet 1625I may be used inconjunction with separately magnetized battery cells.

In a second embodiment, which is illustrated in FIGS. 16J-16L viadifferent side-perspectives, a hold-down mechanism may be implementedvia a hold-down plate that is placed on top of a hybrid contact plate(e.g., any of the hybrid contact plates described above).

Referring to FIG. 16J, a hold-down plate 1600J is shown as mounted ontop of a hybrid contact plate arrangement 1605J (e.g., comprising a“top” multi-layer contact plate, an intervening insulation layer, and a“bottom” multi-layer contact plate), which is in turn mounted on top ofbattery cells 1610J and 1615J. Hold-down elements 1620J, 1625J and 1630Jare connected to the hold-down plate 1600J. The hold-down elements1620J, 1625J and 1630J are protrusions that are aligned with the contactareas where the various bonding connectors are positioned (e.g., overrespective positive and negative terminals of the battery cells 1610Jand 1615J). By aligning these protrusions with bonding connectors andthen applying downward force to the hold-down plate 1600J, the hold-downelements 1620J, 1625J and 1630J in turn apply downward force to therespective bonding connectors in the hybrid contact plate arrangement1605J such that the bonding connectors are bent and pressed down ontorespective terminals. More specifically, the hold-down element 1620Japplies downward force to a “positive” bonding connector that is to beaffixed to a positive cell head of battery cell 1610J, the hold-downelement 1625J applies downward force to a “negative” bonding connectorthat is to be affixed to negative cell rims of battery cells 1610J and1615J, and the hold-down element 1630J applies downward force to a“positive” bonding connector that is to be affixed to a positive cellhead of battery cell 1615J. The shapes of the above-noted protrusionsmay be configured to conform to a desired shape of the bondingconnectors prior to the bonding connectors being welded to therespective terminals. As will be appreciated, the battery cellarrangement depicted in FIG. 16J is an example of a 2-Cell arrangement,as shown in FIG. 16C with respect to 1610C as an example. It will beappreciated that the hold-down plate 1600J may alternatively beconfigured for 1-Cell arrangements (e.g., as in FIG. 16H), 3-Cellarrangements (e.g., 1615C of FIG. 16C), and so on. Also shown in FIG.16J is an elastic element 1635J, which may help for tolerance (e.g., sothat damage is not caused to the hybrid contact plate arrangement 1605J,battery cells 1610J-1615J, and/or the battery housing as downward forceis applied to the hold-down plate 1600J).

Referring to FIG. 16K, a different side-perspective of the hold-downplate 1600J depicted in FIG. 16J is shown. The negative and positivebonding connectors 1600K and 1605K are more clearly illustrated in FIG.16K.

Referring to FIG. 16L, another different side-perspective of thehold-down plate 1600J depicted in FIG. 16J is shown. The negative andpositive bonding connectors 1600K and 1605K are more clearly illustratedin FIG. 16L, as well as negative contact tab 1600L.

As discussed above, battery modules for certain applications, such aselectric vehicles, may be required to provide a fairly high voltageoutput (e.g., 300V-800V or even higher). Due to the high voltage, thereis a possibility that an arc (i.e., an electrical discharge) will occur.Arcs occur when an electrical connection is opened (e.g., by a highcurrent), resulting in a voltage differential. For P groups connected inseries, an arc may be most likely to occur when the last parallelconnection in one of the P groups is opened (e.g., because the currentintended to be handled by the entire P group is instead channeledthrough one particular cell terminal connection, which will then likelybreak). Arcs can involve a high amount of current and can thereby bevery dangerous (e.g., an arc can cause a temperature spike which candamage one or more battery cells in a battery module). Conventionally,the risk of arcs is mitigated by placing insulation between areas with avoltage differential and/or physically separating two areas withdifferent electrical potentials (e.g., increasing a creeping distance).However, it may be difficult to predict precisely where an arc willoccur. For example, in a battery module with a high number of batterycells connected in parallel per P group, an arc could theoreticallyoccur at any of these battery cells.

As noted above, arcs are most likely to occur in a serial circuitarrangement, such as P groups connected in series, when the very lastparallel electrical connection within a particular P group is broken.Generally, as described below with respect to FIGS. 17A-17C, oneparticular parallel electrical connection in a P group may be configuredwith a higher fuse rating (e.g., an amperage at which the fuse isconfigured to break the fuse) than any other in that P group to isolatewhere an arc is most likely to occur so that arc mitigation features canbe deployed at that particular area of a contact plate.

FIG. 17A illustrates a top-perspective of a portion of a multi-layercontact plate 1700A, along with a side-perspective of the multi-layercontact plate 1700A that shows the multi-layer contact plate 1700Aconnected to a top-facing positive terminal of a battery cell inaccordance with an embodiment of the disclosure.

Referring to FIG. 17A, the multi-layer contact plate 1700A includesbonding connectors 1705A, 1710A and 1715A. As discussed above, thebonding connectors 1705A, 1710A and 1715A may either be formed from acell connection terminal layer of the multi-layer contact plate 1700A,or alternatively may be attached (e.g., via welding) specifically nearcontact areas of the multi-layer contact plate 1700A as described abovewith respect to FIGS. 16A-16B.

As shown in FIG. 17A, the bonding connector 1705A is configured with ahigher resistance than bonding connectors 1710A or 1715A, which givesthe bonding connector 1705A a higher fuse rating relative to the bondingconnectors 1710A and 1715A. Below, reference to the higher resistance ofthe “high-fuse” bonding connector is used interchangeably with referenceto a “higher fuse rating” of the “high-fuse” bonding connector as twodifferent alternate ways to characterize this particular characteristicof the “high-fuse” bonding connector. In an example, the higher relativeresistance of the bonding connector 1705A may be implemented in avariety of ways, such as forming the bonding connector 1705A with ahigher resistance material that is different from the material used forthe bonding connectors 1710A or 1715A, configuring the bonding connector1705A with a different geometry (e.g., modifying a shape of the bondingconnector 1705A relative to other bonding connectors by increasing therelative length, thickness, etc. of the bonding connector 1705A), or anycombination thereof. Accordingly, in some implementations, “high-fuse”bonding connectors may be made from a higher-resistant material relativeto the other bonding connectors while having the same or similargeometry (e.g., same shape, thickness, etc.). In other implementations,“high-fuse” bonding connectors may be made from the same material as theother bonding connectors while having a different geometry (e.g.,different shape, thickness, etc.). In yet other implementations,“high-fuse” bonding connectors may be made from a higher-resistantmaterial relative to the other bonding connectors while also having adifferent geometry (e.g., different shape, thickness, etc.).

Referring to FIG. 17A, the bonding connector 1705A includes alower-resistance section 1708A that functions as a fuse for the bondingconnector 1705A. This lower-resistance section 1708A has a higherresistance than the bonding connectors 1710A or 1715A, while having alower relative resistance than the rest of the bonding connector 1705A.Accordingly, when the bonding connector 1705A breaks due to highcurrent, the specific point at which the break of the bonding connector1705A will be expected to occur specifically at the lower-resistancesection 1708A.

In an example, the bonding connectors 1705A, 1710A and 1715A may be madefrom steel, such as Hilumin (e.g., an electro nickel-plated diffusionannealed steel strip for battery applications with low contactresistance and high corrosion resistance). However, as noted above, thebonding connectors 1705A, 1710A and 1715A may also be made from othermaterials (e.g., which may be the same or different from the batterycell terminal material and/or materials used in one or more other layersof the multi-layer contact plate 1700A). Accordingly, as the currentthrough the multi-layer contact plate 1700A increases, the bondingconnectors 1710A and 1715A function as lower-resistance fuses that willbe expected to break before the “high-fuse” bonding connector 1705A. Aswill be appreciated, defining the last bonding connector to break for aP group may help to isolate arc occurrences to that particular bondingconnector, which reduces the area of the multi-layer contact plate thatneeds to be protected against arcs. This in turn saves material costsand simplifies production compared to deploying arc protection for allbonding connectors on the contact plate. Various arc protection featuresthat may be deployed in proximity to the bonding connector 1705A aredescribed below with respect to FIGS. 17B-17C.

While FIG. 17A describes a single “high-fuse” bonding connector for arcprotection, it is theoretically possible for multiple bonding connectorsto be deployed for this purpose in other embodiments (e.g., with arcprotection being deployed with respect to each high-fuse bondingprotector). Also, while FIG. 17A illustrates an example specific to amulti-layer contact plate, it will be appreciated that other embodimentscan deploy high-fuse bonding connector(s) with respect to single-layercontact plates. For example, consider FIGS. 16A-16B where preassembledbonding connectors are simply attached to a contact plate withoutnecessarily requiring a multi-layer contact plate. In this case, one (ormore) of the preassembled bonding connectors can be configured morethickly than the others to achieve a higher fuse rating.

FIG. 17B illustrates a top-perspective of a portion of the multi-layercontact plate 1700A including an insulation layer 1700B stacked thereon,while FIG. 17C illustrates a side-perspective of the multi-layer contactplate 1700A and insulation layer 1700B that shows a respectiveconnection to a top-facing positive terminal of a battery cell inaccordance with an embodiment of the disclosure. In an example, theinsulation layer 1700B may be configured similarly to any of theinsulation layers described above with respect to hybrid contact plates.

Referring to FIGS. 17B-17C, a recessed portion 1705B (or hole) may beintegrated into the insulation layer 1700B in proximity to the bondingconnector 1705A, such that some or all of the lower-resistance section1708A of the bonding connector 1705A is exposed through the recessedportion 1705B. As shown in FIG. 17C, the recessed portion 1705B may befilled with a protective compound (e.g., quartz sand, red phosphor gel,etc.) that is configured to provide arc protection. As noted above, thelower-resistance section 1708A of the bonding connector 1705A may bealigned with the recessed portion 1705B and may be configured with thelowest resistance along the bonding connector 1705A, while still havinghigher resistance than any other “normal” bonding connector. In thiscase, the “high-fuse” bonding connector 1705A may be configured to breakspecifically in the recessed portion 1705B where the protective compoundis provided. The protective compound deployed in the recessed portion1705B may help to cool down the bonding connector 1705A when opening(e.g., after high current is experienced) to ensure to reduce plasmabeing formed from the vaporized metal of the blown fuse. In anotherexample, additional arc protection features can be deployed in proximityto the bonding connector 1705A, such as implementing a magnetic field orair flow to interrupt an arc. These additional arc protection featuresmay be applied specifically to the lower-resistance section 1708A, as anexample. In a further example, the bonding connector 1705A may beimplemented as a melting safety fuse.

Turning back to the general configuration of cylindrical battery cellsas discussed above with respect to FIGS. 4-5, cylindrical battery cellsdeployed in P group arrangements conventionally include positive andnegative terminals at opposite sides of the battery cell. This is inpart due to the conventional layout of contact plates, which generallydo not permit all contact plates to be arranged on the same side of thebattery cells across different P groups. Various embodiments of thedisclosure which have already been described above relate to contactplate arrangements that permit cylindrical battery cells that includeboth top-facing positive and negative terminals to be used, which willnow be discussed in more detail.

FIG. 18A illustrates a conventional multi-terminal cell side 1800A of aconventional cylindrical battery cell. As noted above, while thecylindrical battery cell depicted in FIG. 18A is conventional (e.g., anoff-the-shelf product available on the market), this type of cylindricalbattery cell has generally not been used in association with P grouparrangements in battery modules.

Referring to FIG. 18A, the multi-terminal cell side 1800A includes apositive cell head 1805A (e.g., the positive terminal for the batterycell) that is implemented as a round head in the center or inner portionof the multi-terminal cell side 1800A. In an example, for an 18650 cell,the positive cell head 1805A may occupy an area of approximately 50 mm².The multi-terminal cell side 1800A further includes a negative cell rim1810A (e.g., the negative terminal for the battery cell) arranged alongan outer periphery (or “rim”) of the multi-terminal cell side 1800A. Arecessed area 1815A is arranged between the positive cell head 1805A andthe negative cell rim 1810A. While not expressly shown in FIG. 18A, arelatively thin insulative divider (e.g., made from plastic) may beconfigured between the positive cell head 1805A and the negative cellrim 1810A (e.g., to internally separate the positive and negativeterminals).

FIG. 18B illustrates a multi-terminal cell side 1800B of a cylindricalbattery cell in accordance with an embodiment of the disclosure. Themulti-terminal cell side 1800B includes the positive cell head 1805A,the negative cell rim 1810A, and the recessed area 1815A, similar to themulti-terminal cell side 1800A described above with respect to FIG. 18A.In addition, the multi-terminal cell side 1800B further includes aninsulative ring 1805B (e.g., made from plastic) placed over aninsulative divider (not shown) in the recessed area 1815A between thepositive cell head 1805A and the negative cell rim 1810A. The insulativering 1805B acts as a “wall” or barrier between the positive cell head1805A and the negative cell rim 1810A that may provide a variety ofbenefits, as explained below with respect to FIG. 19.

FIG. 19 illustrates a side-perspective of the multi-terminal cell side1800B of FIG. 18B in accordance with an embodiment of the disclosure. Inparticular, the insulative ring 1805B is shown in more detail in FIG.19, as well as an insulative divider 1900.

Most cylindrical battery cells, such as the 18650 cell, are configuredfor applications with lower voltages. In the future, however, voltagerequirements for certain applications (e.g., electric vehicles) arelikely to increase. Higher-voltage applications may require higherinsulation between the positive cell head 1805A and the negative cellrim 1810A. The insulative ring 1805B increases the insulation betweenthe positive cell head 1805A and the negative cell rim 1810A, which mayincrease a creeping distance (e.g., an electrical creeping distance)between the positive cell head 1805A and the negative cell rim 1810A.The insulative ring 1805B may also protect one pole from the other andfrom sparks during (an optional) welding process. The insulative ring1805B may also be configured to protect against conductive materialleaking out of the cylindrical battery cell in response to anoverpressure condition.

Referring to FIG. 19, the insulative ring 1805B and the insulativedivider 1900 formed in the recessed area 1815A are shown as one joinedlayer (e.g., one piece of plastic), such that the insulative ring 1805Bis part of the insulative divider 1900. However, in other embodiments,the insulative ring 1805B and the insulative divider 1900 may beimplemented as separate components (e.g., two pieces of plastic that areglued together). A groove 1905 may be configured as a fixation element(e.g., to hold the insulative divider 1900 in place). In an example, theinsulative ring 1805B may be arranged (e.g., clamped) between theinner-section of the groove 1905 and the negative cell rim 1810A, asshown in FIG. 19.

Referring to FIG. 19, during construction of the battery cell, batteryfluid material may be filled with the battery cell via an open top. Inan example, once the battery fluid reaches a target fill-level for thebattery cell, the side of the battery cell is crimped to form thenegative cell rim 1810A.

Referring to FIGS. 18-19, the positive cell head 1805A and negative cellrim 1810A may be made from the same material (e.g., steel or Hilumin) insome embodiments. However, it is also possible to configure the positivecell head 1805A and the negative cell rim 1810A in FIGS. 18-19 withdifferent material types in other embodiments (e.g., Al and steel, Cuand Al, Cu and steel, etc.).

Between battery cells connected in serial between respective P groups ina battery module as described above, some form of insulation may beintegrated via an insulator between the respective battery cells. Forexample, cylindrical battery cells may be fixed at their top and bottomin a housing as discussed above with respect to FIG. 14, and aninsulator (e.g., an insulation dividing wall) may be integrated betweenthese top and bottom parts of the battery. However, allocatingadditional space for insulation in the housing may reduce the capacityof a battery module.

FIG. 20 illustrates a cylindrical battery cell 2000 in accordance withan embodiment of the disclosure. The cylindrical battery cell 2000includes a higher insulation area 2005 in a middle-portion of thecylindrical battery cell 2000, a first lower insulation area 2010extending from the multi-terminal cell side 1800B, and a second lowerinsulation area 2015 extending from a side (or end) of the cylindricalbattery cell 2000 that is opposite from the multi-terminal cell side1800B. The higher insulation area 2005 and the first and second lowerinsulation areas 2010-2015 are arranged around the sides (or ends) ofthe cylindrical battery cell 2000 as shown in FIG. 20. Morespecifically, the higher insulation area 2005 is an area where one ormore extra layers of insulation are integrated into the battery cellitself, which reduces the need to use external insulation betweenbattery cells inside of a housing. In an example, the one or more extralayers of insulation (e.g., foil) may be wrapped around the middle areaof the cylindrical battery cell 2000 to form the higher insulation area2005. By contrast, the first and second lower insulation areas 2010-2015omit the one or more extra layers of insulation. In an example, thefirst and second lower insulation areas 2010-2015 may be uninsulated, inthe sense that these sections of the cylindrical battery cell 2000 arecomparable, in terms of insulation, to a conventional cylindricalbattery cell (e.g., an 18650 cell).

Referring to FIG. 20, in an example, the first and second lowerinsulation areas 2010-2015 may be sized so as to align with a portion ofa battery housing that is configured to enclose the cylindrical batterycell 2000. For example, pieces of plastic from the battery housing mayat least partially cover the first and second lower insulation areas2010-2015, such that the extra insulation layer(s) can be omitted inthese particular sections (e.g., comparable levels of insulation may beobtained from the battery housing envelopment over these sections).

FIG. 21 illustrates a side-perspective and a top-perspective of abattery housing 2100 including a number of cylindrical battery cells2005 as described above with respect to FIG. 20 inserted therein inaccordance with an embodiment of the disclosure. The battery housing2100 includes a housing top 2105, a fixation bar 2110, an insulationlayer 2115 (e.g., insulation foil), a housing bottom 2120, and housingribs 2125 which help to separate and electrically insulate battery cellsin different P groups from each other.

By omitting the one or more extra layers of insulation specifically nearthe cell fixation areas of the battery cells, smaller tolerances may beprovided and a more secure connection between the battery cells andtheir fixation points (e.g., holes through which the battery cells aresecured into respective battery cell receptacles via screwing, adhesive,or magnetically) may be facilitated. On the other hand, including theone or more extra layers of insulation of the battery cells in thehigher insulation areas 2005 of the cylindrical battery cells 2000immersed in the battery housing 2100 may increase the creeping distancebetween adjacent battery cells in different P groups. Accordingly, theselective deployment of one or more extra layers of insulation of thebattery cells specifically to a middle-section (or higher insulationarea 2005) permits top-to-bottom insulation divider walls 2130 to beomitted, which facilitates smaller and more uniform distances betweenbattery cells to increase the capacity of the battery module, protectsother battery cells in the battery module from hazard propagation (e.g.,overheating, fire, etc.) in the case of a thermal runaway, and reducesthe inter-cell distance between battery cells (e.g., in particular,between battery cells in adjacent P groups that have differentelectrical potentials and thereby need some form of electricalinsulation from each other).

Also shown in FIG. 21 are exposed portions 2135 of the lower insulationareas 2010-2015. In an example, the higher insulation area 2005 may beconfigured to be somewhat shorter than the housing top 2105 and thehousing bottom 2120, leaving a small part of the lower insulation areas2010-2015 exposed (at top and bottom). The housing ribs 2125 may beconfigured to electrically insulate adjacent P groups from other Pgroups (e.g., due to the different electrical potentials in therespective P groups) by covering the exposed portions 2135 between Pgroups. For example, the housing ribs 2125 (e.g., at both top and bottomof the battery housing 2100) may extend further than the exposedportions 2135 to insulate the exposed portions 2135 of one P group fromthe exposed portions 2135 in a neighboring P group. This functions toincrease the creeping distance between the neighboring P groups. Thehousing ribs 2125 may be arranged at the top of the battery housing 2100(e.g., to cover up a top exposed portion), at the bottom of the batteryhousing 2100 as shown in FIG. 21 (e.g., to cover up a bottom exposedportion), or a combination thereof.

While various embodiments of the disclosure are discussed separatelyabove, a detailed example implementation for a battery module isdescribed below with respect to FIGS. 22A-22H to provide greater clarityin terms of the inter-operability of the various embodiments. For thesake of convenience, certain assumptions are made in the description ofFIGS. 22A-22H which will be appreciated to be strictly for purposes ofexample. In particular, the following non-limiting example assumptionsare made for the battery module system depicted in FIGS. 22A-22H:

-   -   The battery module includes an integrated insertion-side cover;    -   Cooling tubes are integrated into the insertion-side cover;    -   The battery module is configured for side or lateral-insertion        into a corresponding battery module compartment;    -   The HV connectors for the battery module are located on the same        side of the battery module;    -   Cylindrical battery cells with top-facing positive and negative        cell terminals are used in the battery module;    -   A hybrid contact plate arrangement is used in the battery        module; and    -   A hybrid contact plate arrangement comprising multi-layer        contact plates with a “sandwiched” middle layer that forms the        bonding connectors is used in the battery module.

It will be appreciated that each of the aforementioned exampleassumptions is made in a non-limiting manner so as to promote claritywith respect to various embodiments of the disclosure.

Further, FIGS. 22A-22H depict a virtual ‘construction’ of a batterymodule that by starting with an empty shell of a battery module and thenadding (from top to bottom) each of the various components that comprisethe battery module. Many of the successive FIGS. among FIGS. 22A-22H addcomponents to the battery module relative to preceding FIGS. Ascomponents are added to the battery module in successive FIGS.,components that were added in previous FIGS. are assumed to still bepresent unless stated otherwise. Also, the order in which the variouscomponents are added in FIGS. is for the sake of illustrativeconvenience, and does not necessarily mirror the order in which thevarious components are added during assembly of the actual batterymodule. When fully assembled, the battery module described with respectto FIGS. 22A-22H corresponds to the battery module described above withrespect to FIGS. 1-2.

FIG. 22A illustrates a battery module perspective 2200A in accordancewith an embodiment of the disclosure. In FIG. 22A, the battery moduleperspective 2200A depicts part of an exterior frame of the batterymodule with an open top (e.g., through which the various components ofthe battery module may be installed during assembly). In particular, thebattery module perspective 2200A depicts an insertion-side cover 2205A(e.g., similar to insertion-side cover 110 of FIGS. 1-2) includingcooling connections 2210A-2215A (e.g., similar to cooling connections120 of FIGS. 1-2). Also depicted are sidewalls 2220A-2225A, and abackwall 2230A. While not shown expressly in the battery moduleperspective 2200A of FIG. 22A, the backwall 2230A includes fixation andpositioning elements 200, the HV connectors 205, and the LV connector210 depicted in FIG. 2.

FIG. 22B illustrates a battery module perspective 2200B in accordancewith an embodiment of the disclosure. In FIG. 22B, an overpressure valve2205B (e.g., correspond to overpressure valve 125 in FIG. 1) is added tothe insertion-side cover 2205A (e.g., corresponding to fixation points115 in FIG. 1). The flanges and various fixation points of theinsertion-side cover 2205A are omitted for convenience of illustration.Further added in FIG. 22B is cooling tube 2210B, which is connected tothe cooling connectors 2210A-2215A and runs underneath the batterymodule. In particular, the cooling tube 2210B is coupled to a coolingplate (not shown in the battery module perspective 2200B of FIG. 22B)for cooling the battery module.

FIG. 22C illustrates a battery module perspective 2200C in accordancewith an embodiment of the disclosure. In FIG. 22C, a cooling plate 2205Cis added to the battery module perspective 2200B depicted in FIG. 22B,which covers the cooling tube 2210B depicted in FIG. 22B. The coolingplate 2205C may function as both a cooling plate and a floor of thebattery module. Also depicted in FIG. 22C are guiding elements 2210C(e.g., corresponding to guiding elements 105 in FIGS. 1-2), which formpart of the exterior frame of the battery module, and insertion-sidecover 2205A is depicted with additional detail.

FIG. 22D-1 illustrates a battery module perspective 2205D-1 inaccordance with an embodiment of the disclosure. In FIG. 22D, a housingbottom 2205D is added on top of the cooling plate 2205C depicted in thebattery module perspective 2200C of FIG. 22C. In an example, the housingbottom 2205D may be made from plastic and may define battery receptaclesinto which cylindrical battery cells may be inserted, and may alsoinclude housing ribs configured to separate (and help to insulate)adjacent P groups of battery cells, as discussed above with respect toFIG. 21.

To help appreciate the housing bottom 2205D, an alternate viewpoint ofthe battery module perspective 2200D-1 is depicted in FIG. 22D-2. In thealternative battery module perspective 2200D-2, a portion of the housingbottom 2205D is shown. The battery module perspective 2200D-2 moreclearly depicts that the housing bottom 2205D includes a “center”housing rib 2210D that runs lengthwise along the battery module, andseveral “lateral” housing ribs 2215D that run laterally (or widthwise)across the battery module. As noted above with respect to FIG. 21, thehousing ribs (both center and lateral) are slightly raised sections ofthe housing bottom 2205D that can be used to help insulate adjacent Pgroups of battery cells from each other. So, in one example, the“center” and “lateral” housing ribs 2210D-2215D may define sections ofthe housing bottom 2205D allocated to different P groups of batterycells.

FIG. 22E illustrates a battery module perspective 2200E in accordancewith an embodiment of the disclosure. In FIG. 22E, battery cells areinserted into the battery receptacles of the housing bottom 2105Ddepicted in FIGS. 22D-1 and 22D-2. In an example, the cylindricalbattery cells shown as inserted into the battery module in FIG. 22E maycorrespond to the cylindrical battery cells described above with respectto FIGS. 18A-21 (e.g., with top-facing positive cell heads and negativecell rims, and insulated middle sections). Also depicted in FIG. 22E forthe first time in this FIG. sequence are the flanges and fixation points2205E on the insertion-side cover 2205A, so the relevant height of thebattery cells and insertion-side cover can be appreciated. Once again,various features (e.g., individual bolts, screws, etc.), such as theflanges and fixation points of the insertion-side cover 2205A in thepreceding FIGS., have been omitted to increase the overall clarity ofthis sequence of FIGS. by focusing on the more relevant features.

FIG. 22F-1 illustrates a battery module perspective 2200E-1 inaccordance with an embodiment of the disclosure. In FIG. 22F-1, ahousing top 2205F-1 is mounted onto the battery cells depicted in FIG.22E. In an example, the housing top 2205F-1 may be made from plastic.Also, while not expressly shown in FIG. 22F-1, the housing top 2205F-1may include downward-facing housing ribs that are aligned with the“center” and “lateral” housing ribs 2210D-2215D depicted in FIG. 22D-2.So, while the “center” and “lateral” housing ribs 2210D-2215D help toinsulate battery cells in adjacent P groups from each other (e.g., byoverlapping an exposed, non-insulated portion of respective batterycells), corresponding “center” and “lateral” housing ribs may likewisebe implemented into the housing top 2205F-1 to provide a similarfunction (e.g., to overlap with exposed, non-insulated portions ofrespective battery cells and thereby help to insulate P groups from eachother). The housing top 2205F-1 includes holes or openings that arealigned with the contact areas in the hybrid contact plate arrangementmounted therein, which will be described below in more detail. FIG.22F-2 illustrates a particular zoomed-in section 2200E-2 of the batterymodule perspective 2200E-1 depicted in FIG. 22F-1, including a firstcontact area 2205F-2 for a first P group and a second contact area2210E-2 for a second P group. The first and second P groups areconnected in-series via a “center” multi-layer contact plate. Thezoomed-in section 2200E-2 is used below to explain how the variouslayers of the hybrid contact plate arrangement are stacked onto thehousing top 2205F-1.

FIG. 22G-1 illustrates a battery module perspective 2200G-1 inaccordance with an embodiment of the disclosure. In FIG. 22G-1, a hybridcontact plate arrangement 2205G-1 is mounted onto the battery cellsdepicted in FIG. 22E. The hybrid contact plate arrangement 2205G-1includes an arrangement of contact areas, as described above. In thisparticular embodiment, the series-connected P groups of the hybridcontact plate arrangement 2205G-1 are arranged in an upside-downU-shaped pattern, starting with an HV connector 2210G-1 of the “negativepole” multi-layer contact plate, and ending back at an HV connector2215G-1 of the “positive pole” multi-layer contact plate. Arrows in FIG.22G-1 denote the direction of current flow, which in turn marks thearrangement of the series-connected P groups. Moreover, in FIG. 22G-1,the shape or orientation of the individual contact areas are alignedwith the direction of the current flow, which may improve efficiency ofthe current distribution throughout the battery module in at least oneembodiment. Due to the complexity of the hybrid contact platearrangement 2205G-1, a layer-by-layer deconstruction of the hybridcontact plate arrangement 2205G-1 will now be described with respect tothe zoomed-in section 2200E-2 from FIG. 22F-2.

Referring to FIG. 22G-2, multi-layer contact plates 2200G-2 and 2205G-2of the hybrid contact plate arrangement 2205G-1 are shown on top of thezoomed-in section 2200E-2 from FIG. 22F-2. In particular, “positive”bonding connectors 2210G-2 and 2215G-2 of multi-layer contact plate2200G-2 are connected to positive cell heads of two battery cells in afirst P group, and a “negative” bonding connector 2220G-2 of multi-layercontact plate 2205G-2 is connected to negative cell rims of two batterycells in a second P group. The multi-layer contact plates 2200G-2 and2205G-2 may be any type of multi-layer contact plate (e.g., “center”,“negative pole” or “positive pole”, depending on which section of thehybrid contact plate arrangement is being zoomed in upon).

Referring to FIG. 22G-3, an insulation layer 2200G-3 is added on top ofthe multi-layer contact plates 2200G-2 and 2205G-2 shown in FIG. 22G-2.Referring to FIG. 22G-4, a “center” multi-layer contact plate 2200G-4 isadded on top of the insulation layer 2200G-3 shown in FIG. 22G-3. Unlikemulti-layer contact plates 2200G-2 and 2205G-2, the “center” multi-layercontact plate 2200G-4 is configured to connect the first and second Pgroups in series, and thereby includes bonding connector connections toboth P groups. In particular, “positive” bonding connectors 2205G-4 and2210G-4 of “center” multi-layer contact plate 2200G-4 are connected topositive cell heads of two battery cells in the second P group, and a“negative” bonding connector 2215G-4 of “center” multi-layer contactplate 2200G-4 is connected to negative cell rims of two battery cells inthe first P group. As will be appreciated, FIGS. 22G-2 through 22G-4represent example layer-by-layer depictions of the hybrid contact platearrangement 2205G-1 depicted in FIG. 22G-1. After the hybrid contactplate arrangement 2205G-1 is added and the various cell terminalconnections are made (e.g., via welding), the battery module may beenclosed, resulting in the battery module depiction shown in FIGS. 1-2.

FIG. 22H illustrates an HV connector 2200H of the battery module inaccordance with an embodiment of the disclosure. As noted above, the HVconnector 2200H may be implemented as an integrated section of the“negative pole” or “positive pole” multi-layer contact plate thatextends out of the battery module, or alternatively may be a separatecomponent that is merely coupled to the “negative pole” or “positivepole” multi-layer contact plate. In either case, the HV connector 2200His configured to connect to an external HV connector of some sort, suchas an HV plug. For example, the battery module may be configured toslide into a battery module compartment, with the HV plug being alignedwith the HV connector 2200H (e.g., as well as the other HV connector andthe LV connector) so that an HV electrical connection is formed betweenthe HV connector 2200H and the HV plug when the battery module slidesinto the battery module compartment.

While the embodiments described above provide various examples ofmaterials that may be used for different components, it will beappreciated that comparable variants of any of the noted examples mayalso be deployed. Accordingly, references to material types such as Al,Cu and steel are intended to cover not only Al, Cu and steel, but alsoany known alloys thereof.

While the embodiments described above relate primarily to land-basedelectric vehicles (e.g., cars, trucks, etc.), it will be appreciatedthat other embodiments can deploy the various battery-relatedembodiments with respect to any type of electric vehicle (e.g., boats,submarines, airplanes, helicopters, drones, spaceships, space shuttles,rockets, etc.).

While the embodiments described above relate primarily to battery modulecompartments and associated battery modules and insertion-side coversfor deployment as part of an energy storage system for an electricvehicle, it will be appreciated that other embodiments can deploy thevarious battery-related embodiments with respect to any type of energystorage system. For example, besides electric vehicles, the above-notedembodiments can be applied to energy storage systems such as home energystorage systems (e.g., providing power storage for a home power system),industrial or commercial energy storage systems (e.g., providing powerstorage for a commercial or industrial power system), a grid energystorage system (e.g., providing power storage for a public power system,or power grid) and so on.

As will be appreciated, the placement of the various battery modulecompartments in the above-noted embodiments is described as beingintegrated into a vehicle floor of an electric vehicle. However, it willbe appreciated that the general closed compartment profile design may beextended to battery module mounting areas that can be installed in otherlocations within the electric vehicle (e.g., in a trunk of the electricvehicle, behind one or more car seats, under a front-hood of theelectric vehicle, etc.).

The forgoing description is provided to enable any person skilled in theart to make or use embodiments of the invention. It will be appreciated,however, that the invention is not limited to the particularformulations, process steps, and materials disclosed herein, as variousmodifications to these embodiments will be readily apparent to thoseskilled in the art. That is, the generic principles defined herein maybe applied to other embodiments without departing from the spirit orscope of the embodiments of the invention.

What is claimed is:
 1. A method of establishing a direct electrical bondbetween a bonding connector of a contact plate and a battery cell in abattery module, comprising: placing the bonding connector onto anexternal terminal surface of the battery cell with the bonding connectormaking non-flush contact with the external terminal surface; andoscillating a laser over a target range that encompasses both a point ofcontact between the external terminal surface and the bonding connectoras well as an area where a gap exists between the external terminalsurface and the bonding connector due to the non-flush contact, whereinthe oscillating results in the bonding connector being welded onto theexternal terminal surface over the target range.
 2. The method of claim1, wherein the external terminal surface corresponds to a positiveterminal of the battery cell, or wherein the external terminal surfacecorresponds to a negative terminal of the battery cell.
 3. The method ofclaim 2, wherein the oscillating uses a soldering compound.
 4. Themethod of claim 3, wherein the soldering compound includes a reactive emulti-layer foil.
 5. The method of claim 1, further comprising: applyingat least one hold-down mechanism to secure the bonding connector ontothe external terminal surface, the at least one hold-down mechanismincluding a magnetic-based hold-down mechanism; and laser-welding,during the applying, the placed bonding connector to the externalterminal surface.
 6. The method of claim 5, wherein the applyingincludes: placing a magnet in proximity to the battery cell in thebattery module prior to the laser-welding.
 7. The method of claim 6,further comprising: removing the magnet from the battery module afterthe laser-welding.
 8. The method of claim 6, wherein the magnet isplaced beneath the battery cell in the battery module prior to thelaser-welding.
 9. The method of claim 5, wherein the applying includes:magnetizing the battery cell prior to the battery cell being insertedinto the battery module.
 10. The method of claim 9, wherein themagnetizing includes: passing the battery cell through a magnetic coilprior to the battery cell being inserted into the battery module. 11.The method of claim 5, wherein the at least one hold-down mechanismfurther includes a hold-down plate.
 12. The method of claim 1, applyinga hold-down plate to secure the bonding connector onto the externalterminal surface, wherein the hold-down plate includes protrusions thatare configured to be placed over a set of bonding connectors of thecontact plate such that downward force results in the set of bondingconnectors being bent downwards so as to be pressed down onto acorresponding set of external terminal surfaces.
 13. The method of claim12, wherein the hold-down plate includes one or more elastic elements toprotect one or more components of the battery module as the downwardforce is applied.
 14. The method of claim 12, wherein the placingincludes: aligning one of the protrusions of the hold-down plate withthe bonding connector before the bonding connector is in contact withthe external terminal surface of the battery cell, and bending thebonding connector downwards by applying a downward force to thehold-down plate at least until the aligned protrusion presses thebonding connector into contact with the external terminal surface of thebattery cell.